Petition for Writ of Certiorari — Merrick B. Garland, Attorney General, et al., Petitioners v. Michael Cargill
Supreme Court briefApr 6, 2023
Ask Donna
What actually matters in this document.
Text
No.
In the Supreme Court of the United States
MERRICK B. GARLAND, ATTORNEY GENERAL, ET AL.,
PETITIONERS
v.
MICHAEL CARGILL
ON PETITION FOR A WRIT OF CERTIORARI
TO THE UNITED STATES COURT OF APPEALS
FOR THE FIFTH CIRCUIT
PETITION FOR A WRIT OF CERTIORARI
ELIZABETH B. PRELOGAR
Solicitor General
Counsel of Record
BRIAN M. BOYNTON
Principal Deputy Assistant
Attorney General
BRIAN H. FLETCHER
Deputy Solicitor General
MATTHEW GUARNIERI
Assistant to the Solicitor
General
MARK B. STERN
MICHAEL S. RAAB
ABBY C. WRIGHT
BRAD HINSHELWOOD
Attorneys
Department of Justice
Washington, D.C. 20530-0001
SupremeCtBriefs@usdoj.gov
(202) 514-2217
QUESTION PRESENTED
Since 1986, Congress has prohibited the transfer or
possession of any new “machinegun.” 18 U.S.C.
922(o)(1). The National Firearms Act, 26 U.S.C. 5801 et
seq., defines a “machinegun” as “any weapon which
shoots, is designed to shoot, or can be readily restored
to shoot, automatically more than one shot, without
manual reloading, by a single function of the trigger.”
26 U.S.C. 5845(b). The statutory definition also encompasses “any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun.” Ibid.
A “bump stock” is a device designed and intended to
permit users to convert a semiautomatic rifle so that the
rifle can be fired continuously with a single pull of the
trigger, discharging potentially hundreds of bullets per
minute. In 2018, after a mass shooting in Las Vegas
carried out using bump stocks, the Bureau of Alcohol,
Tobacco, Firearms and Explosives (ATF) published an
interpretive rule concluding that bump stocks are machineguns as defined in Section 5845(b). In the decision
below, the en banc Fifth Circuit held that the ATF rule
was unlawful because the statutory definition of “machinegun” does not encompass bump stocks. The question presented is as follows:
Whether a bump stock device is a “machinegun” as
defined in 26 U.S.C. 5845(b) because it is designed and
intended for use in converting a rifle into a machinegun,
i.e., into a weapon that fires “automatically more than
one shot * * * by a single function of the trigger.”
(I)
PARTIES TO THE PROCEEDING
Petitioners (defendants-appellees below) are Merrick B. Garland in his official capacity as Attorney General; Steven Dettelbach, in his official capacity as the
Director of the Bureau of Alcohol, Tobacco, Firearms
and Explosives; the Department of Justice; and the Bureau of Alcohol, Tobacco, Firearms and Explosives. Petitioners Garland and Dettelbach were substituted for
their predecessors in office, former Attorney General
William Barr and former Acting Director Regina Lombardo, during the proceedings below.
Respondent (plaintiff-appellant below) is Michael
Cargill.
RELATED PROCEEDINGS
United States District Court (W.D. Tex.):
Cargill v. Barr, No. 19-cv-349 (Nov. 23, 2020)
United States Court of Appeals (5th Cir.):
Cargill v. Garland, No. 20-51016 (Jan. 6, 2023)
(II)
TABLE OF CONTENTS
Page
Opinions below .............................................................................. 1
Jurisdiction .................................................................................... 1
Statutory and regulatory provisions involved ........................... 2
Statement:
A. Legal background ............................................................ 2
B. Bump stock devices ......................................................... 4
C. The present controversy ................................................. 9
Reasons for granting the petition ............................................. 14
A. Bump stocks are “machineguns” as Congress
defined that term in the National Firearms Act ........ 15
1. Bump stocks create a continuous firing cycle
that is initiated by a “single function of the
trigger” ..................................................................... 15
2. Rifles equipped with bump stocks fire more
than one shot “automatically” after a single
trigger pull ............................................................... 19
3. The court of appeals erred in deeming bump
stocks to be beyond the reach of the statutory
definition .................................................................. 21
B. The decision below creates an acknowledged
circuit conflict ................................................................. 26
C. The question presented is exceptionally important,
and this case is a suitable vehicle ................................. 29
Conclusion ................................................................................... 30
Appendix A — Court of appeals en banc opinion
(Jan. 6, 2023) ............................................... 1a
Appendix B — Court of appeals panel opinion
(Dec. 14, 2021) ........................................... 72a
Appendix C — District court findings of fact and
conclusions of law (Nov. 23, 2020) ........... 92a
Appendix D — Court of appeals order granting
rehearing (June 23, 2022) ...................... 154a
Appendix E — Statutory and regulatory provisions ........ 156a
(III)
IV
TABLE OF AUTHORITIES
Cases:
Page
Akins v. United States, 312 Fed. Appx. 197
(11th Cir.), cert. denied, 557 U.S. 942 (2009) ........... 5, 7, 17
Aposhian v. Barr, 958 F.3d 969 (10th Cir.),
vacated on reh’g, 973 F.3d 1151 (10th Cir. 2020),
reinstated, 989 F.3d 890 (10th Cir. 2021),
cert. denied, 143 S. Ct. 84 (2022) ................................. 26, 27
Aposhian v. Garland, 143 S. Ct. 84 (2022) .......................... 28
Barber v. Thomas, 560 U.S. 474 (2010) ............................... 26
Chevron U.S.A. Inc. v. NRDC, Inc., 467 U.S. 837
(1984) .................................................................................... 27
Guedes v. ATF:
920 F.3d 1 (D.C. Cir. 2019), cert. denied,
140 S. Ct. 789 (2020) .................................................. 27
140 S. Ct. 789 (2020) .................................................. 28, 30
45 F.4th 306 (D.C. Cir. 2022) .............................. 23, 27, 29
Gun Owners of Am., Inc. v. Garland:
19 F.4th 890 (6th Cir. 2021), cert. denied,
143 S. Ct. 83 (2022) .............................................. 25, 26
143 S. Ct. 83 (2022) .......................................................... 28
Liparota v. United States, 471 U.S. 419 (1985) .................. 26
Maracich v. Spears, 570 U.S. 48 (2013)............................... 26
Staples v. United States, 511 U.S. 600 (1994) ............... 18, 19
United States v. Alkazahg, 81 M.J. 764
(N-M. Ct. Crim. App. 2021) ............................................... 28
United States v. Camp, 343 F.3d 743 (5th Cir. 2003) ......... 18
United States v. Carter, 465 F.3d 658 (6th Cir. 2006),
cert. denied, 550 U.S. 964 (2007) ....................................... 18
United States v. Evans, 978 F.2d 1112
(9th Cir. 1992), cert. denied, 510 U.S. 821 (1993)............. 23
V
Cases—Continued:
Page
United States v. Fleischli, 305 F.3d 643
(7th Cir. 2002), cert. denied, 538 U.S. 1001 (2003) ........... 18
United States v. Jokel, 969 F.2d 132 (5th Cir. 1992) .......... 18
Statutes:
Firearms Owners’ Protection Act, Pub. L. No. 99-308,
100 Stat. 449:
§ 101(6), 100 Stat. 450 (18 U.S.C. 921(a)(23)).................. 3
§ 102(9), 100 Stat. 452-453 (18 U.S.C. 922(o)) ....... 3, 156a
Gun Control Act of 1968, Pub. L. No. 90-618,
Tit. II, sec. 201, § 5845(b), 82 Stat. 1231 ............................. 2
National Firearms Act, 26 U.S.C. 5801 et seq. ................... 2
26 U.S.C. 5801-5802......................................................... 29
26 U.S.C. 5822 .................................................................. 29
26 U.S.C. 5841(c) ............................................................... 4
26 U.S.C. 5842(a) ............................................................. 29
26 U.S.C. 5845(b) ........... 2-5, 8, 10, 12, 14-22, 24, 28, 156a
National Firearms Act of 1934, ch. 757, 48 Stat. 1236 ......... 3
Public Safety and Recreational Firearms Use
Protection Act, Pub. L. No. 103-322, Tit. XI,
Subtit. A, 108 Stat. 1996:
§ 110102, 108 Stat. 1996-1998 ........................................... 4
§ 110105, 108 Stat. 2000 .................................................... 4
18 U.S.C. 921(a)(30) (2000) ..................................................... 4
18 U.S.C. 922(v) (2000) ............................................................ 4
Miscellaneous:
ATF, U.S. Dep’t of Justice, National Firearms Act
Handbook (rev. Apr. 2009) .............................................. 3, 4
ATF Ruling 2006-2 (Dec. 13, 2006) .................................. 6, 17
82 Fed. Reg. 60,929 (Dec. 26, 2017) ....................................... 7
83 Fed. Reg. 7949 (Feb. 23, 2018) ........................................ 14
VI
Miscellaneous—Continued:
Page
83 Fed. Reg. 13,442 (Mar. 29, 2018) ....................................... 7
83 Fed. Reg. 66,514 (Dec. 26, 2018) ............... 4-10, 14, 16, 17,
20-22, 25, 29
H.R. Rep. No. 1780, 73d Cong., 2d Sess. (1934) ................. 19
H.R. Rep. No. 495, 99th Cong., 2d Sess. (1986) .................... 3
National Firearms Act: Hearings Before the House
Comm. on Ways and Means on H.R. 9066, 73d
Cong., 2d Sess. (1934) ......................................................... 19
Webster’s New International Dictionary
(2d ed. 1934)......................................................................... 20
In the Supreme Court of the United States
No.
MERRICK B. GARLAND, ATTORNEY GENERAL, ET AL.,
PETITIONERS
v.
MICHAEL CARGILL
ON PETITION FOR A WRIT OF CERTIORARI
TO THE UNITED STATES COURT OF APPEALS
FOR THE FIFTH CIRCUIT
PETITION FOR A WRIT OF CERTIORARI
The Solicitor General, on behalf of the Attorney General et al., respectfully petitions for a writ of certiorari
to review the judgment of the United States Court of
Appeals for the Fifth Circuit in this case.
OPINIONS BELOW
The opinion of the en banc court of appeals (App., infra, 1a-71a) is reported at 57 F.4th 447. An earlier panel
opinion (App., infra, 72a-91a) is reported at 20 F.4th
1004. The opinion of the district court (App., infra, 92a153a) is reported at 502 F. Supp. 3d 1163.
JURISDICTION
The judgment of the court of appeals was entered on
January 6, 2023. The jurisdiction of this Court is invoked under 28 U.S.C. 1254(1).
(1)
2
STATUTORY AND REGULATORY
PROVISIONS INVOLVED
The National Firearms Act, 26 U.S.C. 5801 et seq.,
provides in relevant part:
The term “machinegun” means any weapon which
shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot,
without manual reloading, by a single function of the
trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of
parts designed and intended, for use in converting a
weapon into a machinegun, and any combination of
parts from which a machinegun can be assembled if
such parts are in the possession or under the control
of a person.
26 U.S.C. 5845(b).
Other pertinent statutory and regulatory provisions
are reproduced in the appendix to this petition. App.,
infra, 156a-159a.
STATEMENT
A. Legal Background
The National Firearms Act, 26 U.S.C. 5801 et seq., defines a “machinegun” as “any weapon which shoots, is
designed to shoot, or can be readily restored to shoot,
automatically more than one shot, without manual reloading, by a single function of the trigger.” 26 U.S.C.
5845(b). Since 1968, the definition has also encompassed parts that can be used to convert a weapon into
a machinegun. See Gun Control Act of 1968, Pub. L. No.
90-618, Tit. II, sec. 201, § 5845(b), 82 Stat. 1231. A “machinegun” thus includes “the frame or receiver of any
such weapon, any part designed and intended solely and
3
exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a
machinegun can be assembled if such parts are in the
possession or under the control of a person.” 26 U.S.C.
5845(b).
Congress first regulated the sale and possession of
machineguns in the National Firearms Act of 1934,
ch. 757, 48 Stat. 1236. In 1986, Congress amended Title
18 of the U.S. Code to prohibit the sale and possession of
new machineguns, making it a crime “to transfer or possess a machinegun” unless a governmental entity is involved in the transfer or possession. Firearms Owners’
Protection Act (FOPA), Pub. L. No. 99-308, § 102(9), 100
Stat. 452-453 (18 U.S.C. 922(o)). In enacting that criminal prohibition, Congress incorporated the definition of
“machinegun” from the National Firearms Act. FOPA
§ 101(6), 100 Stat. 450 (18 U.S.C. 921(a)(23)). The 1986
amendments responded in part to evidence before Congress of “the need for more effective protection for law
enforcement officers from the proliferation of machine
guns.” H.R. Rep. No. 495, 99th Cong., 2d Sess. 7 (1986).
The Department of Justice regularly issues guidance
concerning whether specific weapons or devices constitute machineguns. In particular, the Bureau of Alcohol,
Tobacco, Firearms and Explosives (ATF) encourages
manufacturers to submit novel weapons or devices to
the agency, on a voluntary basis, for ATF to assess
whether the weapon or device should be classified as a
machinegun or other registered firearm under the National Firearms Act. See ATF, U.S. Dep’t of Justice,
National Firearms Act Handbook 41 (rev. Apr. 2009)
(NFA Handbook). The classification process enables
ATF to provide manufacturers with “the agency’s offi-
4
cial position concerning the status of the firearms under
Federal firearms laws” and thus to assist manufacturers in “avoid[ing] an unintended classification and violations of the law” before a manufacturer “go[es] to the
trouble and expense of producing” the weapon or device. Ibid.; cf. 26 U.S.C. 5841(c) (requiring manufacturers to “obtain authorization” before making a covered
firearm and to register “the manufacture of a firearm”).
ATF has made clear, however, that “classifications are
subject to change if later determined to be erroneous or
impacted by subsequent changes in the law or regulations.” NFA Handbook 41.
B. Bump Stock Devices
1. In 2004, a federal ban on certain semiautomatic
“assault weapons” expired.1 Since that time, ATF has
received a growing number of classification requests
from inventors and manufacturers seeking to produce
“devices that permit shooters to use semiautomatic rifles to replicate automatic fire,” but “without converting
these rifles into ‘machineguns.’ ” 83 Fed. Reg. 66,514,
66,515-66,516 (Dec. 26, 2018). Whether such devices fall
within the statutory definition of a “machinegun” turns
on whether they allow a shooter to fire “automatically
more than one shot * * * by a single function of the
trigger.” 26 U.S.C. 5845(b).
One such type of device is generally referred to as a
“bump stock.” ATF first encountered bump stocks in
2002, when it received a classification request for the
“Akins Accelerator.” 83 Fed. Reg. at 66,517. The Akins
18 U.S.C. 921(a)(30), 922(v) (2000). Those provisions had been
enacted in 1994 with a ten-year sunset provision. See Public Safety
and Recreational Firearms Use Protection Act, Pub. L. No. 103-322,
Tit. XI, Subtit. A, §§ 110102, 110105, 108 Stat. 1996-1998, 2000.
1
5
Accelerator, which attached to a standard semiautomatic rifle, used a spring to harness the recoil energy of
each shot, causing “the firearm to cycle back and forth,
impacting the trigger finger” repeatedly after the first
pull of the trigger. Ibid. Thus, by pulling the trigger
once, the shooter “initiated an automatic firing sequence” that was advertised as firing “approximately
650 rounds per minute.” Ibid.
ATF initially declined to classify the Akins Accelerator as a machinegun because the agency “interpreted
the statutory term ‘single function of the trigger’ to refer to a single movement of the trigger.” 83 Fed. Reg.
at 66,517. In 2006, however, ATF revisited that determination and concluded that “the best interpretation of
the phrase ‘single function of the trigger’ includes a ‘single pull of the trigger.’ ” Ibid. The agency explained
that the Akins Accelerator created “a weapon that ‘with
a single pull of the trigger initiates an automatic firing
cycle that continues until the finger is released, the
weapon malfunctions, or the ammunition supply is exhausted.’ ” Ibid. (brackets and citation omitted). Accordingly, ATF reclassified the device as a machinegun
under the statute. See ibid.
When the inventor of the Akins Accelerator challenged ATF’s classification, the Eleventh Circuit upheld the determination. The court explained that interpreting the phrase “ ‘single function of the trigger’ ” in
Section 5845(b) to mean “ ‘single pull of the trigger’ is
consonant with the statute and its legislative history,”
and that “[t]he plain language of the statute defines a
machinegun as any part or device that allows a gunman
to pull the trigger once and thereby discharge the firearm repeatedly.” Akins v. United States, 312 Fed.
6
Appx. 197, 200-201 (11th Cir.) (per curiam), cert. denied,
557 U.S. 942 (2009).
In 2006, in anticipation of similar future classification
requests, ATF issued a public ruling announcing its interpretation of “single function of the trigger.” ATF
Ruling 2006-2, at 1 (Dec. 13, 2006). ATF explained that,
after reviewing the text of the National Firearms Act
and its legislative history, the agency had concluded that
the phrase “single function of the trigger” includes a
“single pull of the trigger.” Id. at 2. When ATF reclassified the Akins Accelerator, however, it also advised
owners of the device that “removal and disposal of the
internal spring * * * would render the device a nonmachinegun under the statutory definition,” 83 Fed.
Reg. at 66,517, on the theory that, without the spring, the
device would no longer operate “automatically.”
ATF soon received classification requests for bump
stock devices that did not include internal springs.
Those bump stocks replace the standard stock on an ordinary semiautomatic firearm. Unlike a regular stock,
a bump stock channels the recoil from the first shot into
a defined path, allowing the weapon contained within
the stock to slide back a short distance—approximately
an inch and a half—and shifting the trigger away from
the shooter’s trigger finger. 83 Fed. Reg. at 66,532.
This separation allows the firing mechanism to reset.
Ibid. When the shooter maintains constant forward
pressure on the weapon’s barrel-shroud or fore-grip,
the weapon slides back along the bump stock, causing
the trigger to “bump” the shooter’s stationary finger
and fire another bullet. Ibid. In a series of classification letters between 2008 and 2017, ATF concluded that
such devices did not enable a gun to fire “ ‘automatically’ ”
and were therefore not “machineguns.” Id. at 66,517.
7
2. In 2017, a shooter used semiautomatic weapons
equipped with bump stock devices to murder 58 people
and wound 500 more in Las Vegas. 83 Fed. Reg. at
66,516. The bump stock devices allowed the shooter to
rapidly fire “several hundred rounds of ammunition”
into a large crowd attending an outdoor concert. Ibid.
The Las Vegas mass shooting led ATF to review its
prior classifications of bump stock devices. Ibid. In December 2017, ATF published an advance notice of proposed rulemaking, seeking public comment on “the
scope and nature of the market for bump stock type devices.” 82 Fed. Reg. 60,929, 60,930 (Dec. 26, 2017).
On March 29, 2018, ATF published a notice of proposed rulemaking regarding amendments to the definition of “machinegun” in three ATF regulations. See 83
Fed. Reg. 13,442, 13,457 (Mar. 29, 2018). The notice
stated that ATF’s post-2006 classification letters addressing bump stocks without internal springs did “not
reflect the best interpretation of the term ‘machinegun.’ ” Id. at 13,443. The notice further stated that
ATF had “applied different understandings of the term
‘automatically’ ” over time in reviewing bump stocks and
that the agency had “authority to ‘reconsider and rectify’ potential classification errors.” Id. at 13,445-13,446
(quoting Akins, 312 Fed. Appx. at 200). The notice proposed to “clarify that all bump-stock-type devices are
‘machineguns’ ” under the statutory definition. Id. at
13,443. The notice elicited more than 186,000 comments. See 83 Fed. Reg. at 66,519.
ATF published a final rule on December 26, 2018. 83
Fed. Reg. at 66,514. The final rule amended ATF’s regulations to address the terms “single function of the
trigger” and “automatically” as used in the definition of
“machinegun” in order to clarify that bump stock de-
8
vices are machineguns under Section 5845(b). Id. at
66,553-66,554. In the preamble to the rule, the agency
stated that it continued to adhere to its previous understanding that the phrase “ ‘single function of the trigger’ ”
includes a “ ‘single pull of the trigger,’ ” while clarifying
that the phrase also includes motions “analogous” to a single pull. Id. at 66,515. ATF also determined that, under
the “best interpretation of the statute,” id. at 65,521, the
term “automatically” includes functioning “as the result
of a self-acting or self-regulating mechanism that allows
the firing of multiple rounds through a single pull of the
trigger,” id. at 66,519.
ATF further explained that, notwithstanding its
prior classification letters, the agency had concluded
that bump stocks “are machineguns” as defined by Congress in Section 5845(b). 83 Fed. Reg. at 66,515. Bump
stocks enable a shooter to engage in a continuous firing
sequence that occurs “automatically.” Id. at 66,531. As
the shooter’s trigger finger remains stationary on the
ledge provided by the design of the device and the
shooter applies constant forward pressure with the nontrigger hand on the barrel or fore-grip of the weapon,
the firearm’s recoil energy is directed into a continuous
back-and-forth cycle without “the need for the shooter
to manually capture, harness, or otherwise utilize this
energy to fire additional rounds.” Id. at 66,532. A bump
stock thus constitutes a “self-regulating” or “self-acting”
mechanism that allows the shooter to attain continuous
firing after a single pull of the trigger and, accordingly,
is a machinegun. Ibid.; see id. at 66,514, 66,518.
ATF rescinded its prior letters concluding that certain bump stocks were not machineguns. See 83 Fed.
Reg. at 66,530-66,531. The agency also provided instructions for “[c]urrent possessors” of bump stocks “to
9
undertake destruction of the devices” or to “abandon
[them] at the nearest ATF office” to avoid liability under the statute. Id. at 66,530.
C. The Present Controversy
1. Respondent purchased two bump stocks in April
2018, during the rulemaking process. App., infra, 117a.
After ATF adopted the final rule, respondent “surrendered [his bump stocks] to ATF on March 25, 2019.” Id.
at 118a. On the same day, respondent brought this action in the Western District of Texas challenging the
rule on various grounds. Id. at 93a. The case proceeded
to a bench trial, after which the district court entered
judgment for the government. Id. at 92a-153a.
In its post-trial findings of fact, the district court
credited the testimony of an ATF expert who explained
how bump stocks operate to create a continuous “firing
cycle.” App., infra, 106a (citation omitted). The type of
bump stock at issue here is manufactured with a “sliding shoulder stock” and “a ‘trigger ledge,’ on which the
shooter places his finger.” Id. at 103a. The ATF expert
explained that, to initiate the firing sequence, the
shooter puts his trigger finger on the ledge and
“presses forward on the firearm” with his non-trigger
hand, causing the trigger to slide forward in the sliding
shoulder stock. Ibid. Once the trigger engages with the
stationary trigger finger, the bump stock device harnesses the “recoil energy” from each fired bullet to
cause the rifle to “slide[] back and forth” in the sliding
stock, “bump[ing] the trigger finger into the trigger to
continue firing until the shooter stops pushing forward
with his non-shooting hand or the weapon runs out of
ammunition or malfunctions.” Ibid.
The district court agreed with ATF’s view that the
statutory term “single function of the trigger” includes
10
“a single pull of the trigger and analogous motions.”
App., infra, 139a (citation omitted). And the court determined that bump stocks enable firing more than one
shot by a single pull of the trigger “from the perspective
of the shooter,” who initiates the continuous firing sequence by pushing the trigger into contact with his stationary finger a single time, after which the device itself
harnesses recoil energy to create a back-and-forth cycle
of continuously bumping and resetting the trigger
against the shooter’s finger. Id. at 145a (citation omitted). Although the shooter must continue to exert “forward pressure on the fore-end of the gun” with his nontrigger hand in order to continue firing, the court observed that such pressure is no different than “continuing to hold the trigger of a fully automatic weapon.”
Ibid. The court also found that a bump stock creates a
weapon that fires more than one shot “automatically,”
26 U.S.C. 5845(b), because the device—with its extension ledge and recoil channeling—is a “self-acting or
self-regulating mechanism” that enables continuous
fire. App., infra, 141a (citation omitted).
2. A unanimous panel of the court of appeals affirmed. App., infra, 72a-91a. The panel “agree[d] with
the district court that bump stocks qualify as machine
guns under the best interpretation of the statute.” Id.
at 73a. The panel found “compelling” ATF’s interpretation in the final rule that the statutory phrase “ ‘single
function of the trigger’ ” encompasses a “ ‘single pull of
the trigger and analogous motions.’ ” Id. at 80a (quoting
83 Fed. Reg. at 66,553). The panel observed that, “at
the time the [definition] was enacted,” the terms “ ‘function’ ” and “ ‘pull’ ” were “used almost interchangeably in
the context of firearms.” Id. at 80a-81a. The panel also
observed that, “in ordinary English, firearm triggers
11
typically ‘function’ by means of a shooter’s ‘pull.’ ” Id.
at 81a. And the panel determined that a rifle modified
with a bump stock satisfies the statutory definition because “a single trigger pull * * * initiates a firing sequence that continues to fire as long as the shooter continues to push forward” on the front of the weapon with
his non-shooting hand. Id. at 84a (citation omitted).
The panel thus rejected respondent’s argument that
a bump stock does not fire multiple rounds by a “single
function of the trigger” because the trigger resets before each round. App., infra, 80a (citation omitted).
The panel explained that respondent’s interpretation
would “effectively rewrit[e] the statute” so that it defines a machinegun as “a weapon which shoots more
than one shot ‘every time the trigger functions’ rather
than ‘by a single function of the trigger.’ ” Id. at 83a.
The panel likewise rejected respondent’s contention
that a rifle equipped with a bump stock does not fire
more than one shot “automatically.” App., infra, 85a.
The panel emphasized that the final rule’s definition of
“ ‘automatically’ ” is based on “a nearly word-for-word
copy of the dictionary definition,” id. at 86a, and that
the term as used here “ ‘delineates how the discharge of
multiple rounds from a weapon occurs: as the result of
a self-acting mechanism’ which ‘is set in motion by a single function of the trigger,’ ” ibid. (citation omitted).
The panel concluded that a weapon modified with a
bump stock fires multiple shots as the result of a selfregulating mechanism because the weapon “continue[s]
firing until the shooter stops pushing forward with his
non-shooting hand or the weapon runs out of ammunition or malfunctions.” Id. at 88a (quoting the district
court’s findings).
12
3. The court of appeals granted rehearing en banc,
which had the effect of vacating the panel opinion. App.,
infra, 154a-155a. After additional briefing and argument, the en banc court reversed and remanded. Id. at
1a-71a. Thirteen of the 16 participating judges voted to
reverse. Id. at 2a n.*. But the only ground for reversal
on which a majority agreed was the proposition that
“lenity” requires interpreting the statutory definition of
machinegun not to encompass bump stocks. Ibid.
a. Judge Elrod authored the lead opinion. App., infra, 1a-49a. In the portion of that opinion joined by a
majority, the court of appeals assumed arguendo that
Section 5845(b) is ambiguous in two respects: “whether
‘a single function of the trigger’ refers to the firearm’s
mechanics or to the shooter’s pulling of the trigger,”
and whether “the process of engaging the trigger and
maintaining forward pressure on the gun’s forebody
produces ‘automatic’ fire.” Id. at 43a-44a. The court
further stated that the “rule of lenity demands that [the
court] resolve that ambiguity in favor of [respondent],
and in turn conclude that a non-mechanical bump stock
is not a machinegun.” Id. at 45a. The court recognized,
however, that “three of [its] sister circuits” had rejected
challenges seeking to enjoin the same rule. Id. at 16a.
Judge Elrod and a plurality of seven other members
of the court of appeals also took the view that the statutory phrase “single function of the trigger” unambiguously refers to a single mechanical “action” of the trigger, and that a bump stock does not “fire[] more than
one shot each time the trigger ‘acts.’ ” App., infra, 20a;
see id. at 20a-27a. The plurality further concluded that
a bump stock does not permit firing more than one shot
“automatically” because, “to continue the firing after
the shooter pulls the trigger, he or she must maintain
13
manual, forward pressure on the barrel and manual,
backward pressure on the trigger ledge.” Id. at 29a.
Having found the rule inconsistent with the statute,
the court of appeals remanded to the district court.
App., infra, 49a. Judge Elrod’s opinion instructed the
district court to enter judgment for respondent and to
“determine what remedy—injunctive, declarative, or
otherwise—is appropriate.” Id. at 47a.
b. Judge Haynes, joined by Chief Judge Richman,
concurred in the judgment, explaining that she had “reluctantly conclude[d] that the relevant statute is ambiguous such that the rule of lenity favors the citizen in this
case.” App., infra, 49a.
c. Judge Ho, joined by Chief Judge Richman and
Judge Southwick, concurred in part and concurred in
the judgment. App., infra, 49a-62a. Judge Ho acknowledged that bump stocks allow a shooter with a semiautomatic rifle to “simulate the experience of firing an automatic machinegun” and “achieve the same lethality as
fully automatic machineguns.” Id. at 52a. He also rejected the plurality’s conclusion that the statutory definition of machinegun unambiguously excludes bump
stocks. Id. at 57a-58a nn.1-2. But he concluded that the
competing interpretive arguments stand in “equipoise,”
and he therefore invoked the rule of lenity. Id. at 58a.
d. Judge Higginson, joined by Judges Dennis and
Graves, dissented “[f ]or the reasons stated in the panel
opinion.” App., infra, 63a; see id. at 63a-71a. In their
view, the majority had improperly invoked the rule of
“lenity to rewrite a vital public safety statute” and to
“legalize an instrument of mass murder” that Congress
had prohibited. Id. at 71a. The dissenting judges also
observed that the majority had adopted a reading that
14
“conflicts with how every other circuit has interpreted”
the statute. Id. at 68a.
4. On remand, the district court entered judgment
for respondent. D. Ct. Doc. 65, at 1 (Mar. 6, 2023). Respondent then filed a motion requesting that the court
grant additional relief, including nationwide vacatur of
the final rule. D. Ct. Doc. 68, at 1 (Mar. 28, 2023); see
id. at 5-7. The court has not acted on that motion as of
the filing of this petition.
REASONS FOR GRANTING THE PETITION
In the wake of a horrific mass shooting in Las Vegas,
in which bump stocks enabled a gunman to fire hundreds of bullets into a crowd in a matter of minutes,
then-President Trump ordered ATF to reevaluate
whether bump stocks satisfy the definition of “machinegun” in the National Firearms Act. 26 U.S.C.
5845(b); see 83 Fed. Reg. 7949, 7949 (Feb. 23, 2018).
ATF solicited public comment and ultimately concluded
that bump stocks are machineguns under the “best interpretation” of the statute. 83 Fed. Reg. at 66,521.
ATF therefore rescinded its erroneous prior classification letters and published an interpretive rule recognizing that bump stocks are, in fact, machineguns. See id.
at 66,553-66,554. The interpretive rule did not alter or
enlarge the scope of the statutory prohibition on possessing or transferring new machineguns. The rule instead merely served to inform the public of ATF’s considered view that bump stocks are “machineguns” as
Congress defined that term.
Before the decision below, the Sixth, Tenth, and D.C.
Circuits had all rejected challenges to ATF’s final rule,
and this Court had declined to grant further review in
those cases. See pp. 26-27, infra. Here, however, the
Fifth Circuit held in a fractured en banc decision that
15
bump stocks do not satisfy the statutory definition of
“machinegun.” Eight members of the court would have
held that the definition “unambiguously” excludes
bump stocks, but eight other members disagreed. App.,
infra, 2a n.*. The only ground for reversal that commanded a majority was “lenity.” Ibid.
Lenity has no role to play here because the traditional tools of statutory interpretation demonstrate that
bump stocks are “machinegun[s]” under the best reading of the statutory definition. Bump stocks allow a
shooter to fire hundreds of bullets a minute by a single
pull of the trigger. Like other machineguns, rifles modified with bump stocks are exceedingly dangerous; Congress prohibited the possession of such weapons for
good reason. The decision below contradicts the best
interpretation of the statute, creates an acknowledged
circuit conflict, and threatens significant harm to public
safety. This Court should grant the petition for a writ
of certiorari and reverse.
A. Bump Stocks Are “Machineguns” As Congress Defined
That Term In The National Firearms Act
Bump stocks are machineguns because they allow a
shooter to fire “automatically more than one shot * * *
by a single function of the trigger.” 26 U.S.C. 5845(b).
That conclusion follows directly from the statutory text,
and the court of appeals erred in invoking the rule of
lenity to conclude otherwise.
1. Bump stocks create a continuous firing cycle that is
initiated by a “single function of the trigger”
In order to constitute a “machinegun” under the National Firearms Act, a weapon must be capable of firing
more than one shot “by a single function of the trigger.”
26 U.S.C. 5845(b). Rifles modified with bump stocks
16
satisfy that requirement because they enable the
shooter to initiate a continuous firing cycle in response
to a “single pull of the trigger” or an analogous motion.
83 Fed. Reg. at 66,534.2
On a typical semiautomatic rifle, the shooter initiates
the firing sequence by pulling backwards on a curved
trigger to fire a single shot. For each subsequent shot,
the shooter must release his pull on the trigger, so that
the internal hammer mechanism can reset, before pulling the trigger again. See App., infra, 6a (diagram). On
a typical machinegun, by contrast, the shooter initiates
a continuous firing cycle by pulling backwards on the
trigger and maintaining pressure on it; while the
shooter holds the trigger down, the weapon continues to
fire until all the ammunition is exhausted.
As explained above (at pp. 4-6), a bump stock replaces the standard stationary stock on a semiautomatic
rifle with a sliding stock, which is attached to a grip with
an “extension ledge” where the shooter rests his trigger
finger. 83 Fed. Reg. at 66,516. The shooter activates
the trigger either by pulling back on it or by sliding the
trigger forward to make contact with the shooter’s stationary finger on the trigger ledge. App., infra, 103a.
In either design, the bump stock “harnesses and directs
the firearm’s recoil energy to slide the firearm back and
forth so that the trigger automatically re-engages by
‘bumping’ the shooter’s stationary finger without additional physical manipulation of the trigger by the
shooter.” 83 Fed. Reg. at 66,516. This creates a continThe statutory definition also encompasses “any part designed
and intended solely and exclusively * * * for use in converting a
weapon into a machinegun.” 26 U.S.C. 5845(b). Accordingly, if a
rifle modified with a bump stock constitutes a “machinegun,” then
the bump stock device itself is also a “machinegun.” Ibid.
2
17
uous fire-recoil-bump-fire sequence that converts a
semiautomatic rifle into a weapon capable of firing hundreds of rounds per minute.
The continuous firing sequence enabled by a bump
stock is initiated by a “single function of the trigger.”
26 U.S.C. 5845(b). As ATF explained in the final rule, a
single function of the trigger includes, at a minimum, a
“single pull of the trigger.” 83 Fed. Reg. at 66,55366,554. ATF first recognized as much in 2006, when it
reclassified the Akins Accelerator. See ATF Ruling
2006-2, at 1 (discussed at p. 6, supra). Like the bump
stocks at issue here, the Akins Accelerator enabled the
weapon to recoil within the stock, “permitting the trigger to lose contact with the finger” and reset itself. 83
Fed. Reg. at 66,517. “Springs in the Akins Accelerator
then forced the rifle forward, forcing the trigger against
the finger” in a back-and-forth cycle that enabled continuous firing. Ibid. In Akins v. United States, 312 Fed.
Appx. 197 (per curiam), cert. denied, 557 U.S. 942
(2009), the Eleventh Circuit upheld ATF’s “ ‘single pull
of the trigger’ ” interpretation, explaining that the
“plain language of the statute defines a machinegun as
any part or device that allows a gunman to pull the trigger once and thereby discharge the firearm repeatedly.” Id. at 200-201.
The rule at issue here reiterates the same interpretation upheld in Akins. See 83 Fed. Reg. at 66,53466,535. Once the trigger has performed its function of
initiating the firing sequence, a bump stock ensures that
the sequence will continue as long as the shooter maintains forward pressure on the front of the weapon with
his non-trigger hand. See App., infra, 103a-104a. The
trigger mechanism itself resets before each additional
shot, but that process happens automatically by design.
18
And the fact that bump stocks automate the back-andforth movement of the trigger rather than the internal
movement of the hammer does not take them outside
the statutory definition of a “machinegun.” Either way,
the shooter initiates the continuous firing of more than
one shot by a single pull of the trigger and hence “by a
single function of the trigger.” 26 U.S.C. 5845(b).
ATF’s interpretation accords with the ordinary
meaning of the term “trigger.” As the Fifth Circuit itself has previously explained, the “trigger” of a firearm
is the “mechanism that is used to initiate the firing sequence.” United States v. Jokel, 969 F.2d 132, 135
(1992) (per curiam). And the courts of appeals have uniformly recognized that the term “trigger” encompasses
buttons, switches, or other devices for initiating the firing sequence—not just the typical curved metal lever
used in most firearms. See ibid.; see also, e.g., United
States v. Carter, 465 F.3d 658, 665 (6th Cir. 2006) (per
curiam), cert. denied, 550 U.S. 964 (2007); United States
v. Camp, 343 F.3d 743, 745 (5th Cir. 2003); United
States v. Fleischli, 305 F.3d 643, 655 (7th Cir. 2002),
cert. denied, 538 U.S. 1001 (2003). The “trigger” is thus
defined by its function of initiating the firing sequence,
not by its precise form. And with a bump stock, the
shooter need only pull the trigger a single time for the
trigger to perform its function of initiating the continuous firing cycle.
ATF’s interpretation also accords with how courts
have paraphrased the scope of Section 5845(b) in plain
English. In most firearms, the shooter initiates the firing sequence by pulling a trigger, which is why courts
have “instinctively reached for the word ‘pull’ when discussing the statutory definition of machinegun.” App.,
infra, 138a (citation omitted). In Staples v. United
19
States, 511 U.S. 600 (1994), for example, this Court observed that a “machinegun” under the National Firearms Act is a weapon that “fires repeatedly with a single
pull of the trigger.” Id. at 602 n.1 (emphasis added).
The same usage is reflected in the legislative record
preceding Congress’s original adoption of the statutory
definition. The relevant committee report noted that
the bill “contain[ed] the usual definition of machine gun
as a weapon designed to shoot more than one shot without reloading and by a single pull of the trigger.” H.R.
Rep. No. 1780, 73d Cong., 2d Sess. 2 (1934). And the
then-president of the National Rifle Association had
proposed during earlier hearings that a machinegun
should be defined as a weapon “which shoots automatically more than one shot without manual reloading, by
a single function of the trigger.” National Firearms
Act: Hearings Before the House Comm. on Ways and
Means on H.R. 9066, 73d Cong., 2d Sess. 40 (1934)
(statement of Karl T. Frederick, President, National
Rifle Association of America). Explaining that proposal, he stated that “[t]he distinguishing feature of a
machine gun is that by a single pull of the trigger the
gun continues to fire as long as there is any ammunition,” and that any weapon “which is capable of firing
more than one shot by a single pull of the trigger, a single function of the trigger, is properly regarded, in my
opinion, as a machine gun.” Ibid.
2. Rifles equipped with bump stocks fire more than one
shot “automatically” after a single trigger pull
The statutory definition of “machinegun” requires
not only that the firing of more than one shot be initiated by a single function of the trigger but also that it
occur “automatically.” 26 U.S.C. 5845(b). ATF’s final
rule marked a departure in the agency’s understanding
20
of that term as applied to bump stocks, which the
agency acknowledged and fully explained. In previous
classification letters, ATF had concluded that certain
bump stocks were not machineguns because they lacked
“automatically functioning mechanical parts or springs”
of the kind found in the original Akins Accelerator. 83
Fed. Reg. at 66,518. But ATF had issued those letters
without any “substantial or consistent legal analysis” of
the term “ ‘automatically.’ ” Ibid. The agency undertook
such an analysis in the wake of the Las Vegas shooting
and concluded that the term “automatically” is best understood to mean “as the result of a self-acting or selfregulating mechanism.” Id. at 66,519. That definition
was drawn “nearly word-for-word” from contemporaneous dictionaries. App., infra, 86a (panel opinion); see 83
Fed. Reg. at 66,519 (“The word ‘automatically’ is the
adverbial form of ‘automatic,’ meaning ‘having a selfacting or self-regulating mechanism that performs a required act at a predetermined point in an operation.’’)
(quoting Webster’s New International Dictionary 187
(2d ed. 1934)) (brackets omitted).
ATF also correctly determined that bump stocks enable firing more than one shot as a result of a self-acting
or self-regulating mechanism (i.e., automatically), even
in designs lacking mechanical springs. The firing sequence of a rifle modified with a bump stock is “ ‘automatic’ because the device harnesses the firearm’s recoil
energy in a continuous back-and-forth cycle” initiated
by a single trigger pull. 83 Fed. Reg. at 66,519. Indeed,
the entire point of a bump stock is to permit a semiautomatic rifle to fire “automatically,” 26 U.S.C. 5845(b),
through the self-acting mechanism of the device itself.
After a single trigger pull, the bump stock “direct[s] the
recoil energy of the discharged rounds into the space
21
created by the sliding stock (approximately 1.5 inches)
in constrained linear rearward and forward paths.” 83
Fed. Reg. at 66,532 (citation omitted). The trigger
mechanism resets before bouncing back into contact
with the shooter’s stationary finger, at which point another shot is fired and the recoil energy is again harnessed to continue the fire-recoil-bump-fire sequence.
See ibid.
That process is “[s]elf-acting under conditions fixed
for it” and therefore automatic, 83 Fed. Reg. at 66,519
(citation omitted), even in bump stock designs where
the shooter must maintain forward pressure on the
front of the weapon with the non-trigger hand in order
to continue firing—as both the panel and the district
court correctly concluded here. See App., infra, 85a88a, 140a-145a. The pressure that the shooter must
maintain on the front of a weapon modified with such a
bump stock is no different than the pressure a shooter
must maintain on the trigger of a conventional machinegun to engage in continuous fire. That some human input is required does not mean the device ceases
to function “automatically.” An automatic sewing machine, for example, may still require manually feeding
fabric into the machine, and an automatic teller machine
may still require manually selecting how much money
to withdraw. So too here: The user must maintain forward pressure on the front of the weapon, but the bump
stock device itself still automates the firing sequence,
harnessing the recoil energy from each shot to create a
self-acting cycle initiated by a single pull of the trigger.
3. The court of appeals erred in deeming bump stocks to
be beyond the reach of the statutory definition
The court of appeals erred in holding that bump
stock devices are not “machinegun[s].” 26 U.S.C.
22
5845(b). Neither the plurality nor the majority identified any persuasive reason for disregarding the interpretation ATF adopted in its final rule.
a. An eight-judge plurality reasoned that bump
stocks do not qualify as machineguns even if the statutory phrase “single function of the trigger” is interpreted to include a “single pull of the trigger,” App., infra, 20a (quoting 83 Fed. Reg. at 66,553), on the theory
that the shooter operating a rifle with a bump stock still
“pulls the trigger * * * each time he or she fires a bullet,” ibid. The plurality thus would have treated each
instance in which the trigger slides forward and bumps
the shooter’s finger as a separate “pull of the trigger.”
Ibid. That theory has no basis in any recognized understanding of the term “pull,” particularly in the context
of firearms. In ordinary English, no one would say that
a shooter pulled the trigger when an automated device
caused the trigger to be engaged against the shooter’s
stationary finger.
The plurality also endorsed respondent’s alternative
theory, under which “function of the trigger” refers to
“the movement of the trigger itself.” App., infra, 21a22a. The plurality stated that the continuous fire-recoilbump-fire cycle created by bump stocks involves more
than a single function of the trigger because Congress
wrote the statutory definition “from a mechanical perspective,” rather than “based on the shooter’s perspective.” Id. at 23a. On that view, the relevant question is
how many times the trigger itself “function[s]” mechanically in the firing sequence, 26 U.S.C. 5845(b), not how
many times the shooter pulls the trigger.
The plurality’s view that the statutory definition focuses exclusively on mechanical functioning, without regard to actions of the shooter, is mistaken. The imme-
23
diately adjacent clause refers to “manual” reloading,
i.e., reloading by hand. See 26 U.S.C. 5845(b) (“automatically more than one shot, without manual reloading, by a single function of the trigger”) (emphasis
added). That is a textual reference to the human being
operating the weapon, not simply the mechanics of the
weapon itself. Even focusing only on the phrase “by a
single function of the trigger,” ibid., the plurality’s view
fails to take account of the preposition “by” and thus
overlooks the function of the prepositional clause in the
definition read as a whole. The clause specifies that the
automatic firing of more than one shot must occur
“ ‘by,’ ” i.e., “ ‘through the means of ’ or ‘in consequence
of,’ ” a single function of the trigger. Guedes v. ATF, 45
F.4th 306, 316 (D.C. Cir. 2022) (Guedes II) (citation
omitted). Bump stocks satisfy that requirement. The
shooter’s single pull of the trigger is the means of initiating a continuous cycle of firing more than one shot.
Ibid.; see United States v. Evans, 978 F.2d 1112, 1113
n.2 (9th Cir. 1992) (“As used in § 5845(b), ‘by a single
function of the trigger’ describes the action that enables
the weapon to ‘shoot . . . automatically . . . without
manual reloading,’ not the ‘trigger’ mechanism.”), cert.
denied, 510 U.S. 821 (1993).
If the plurality’s reading were correct, then even the
original Akins Accelerator was not a machinegun. Yet
the plurality was unwilling to embrace that logical consequence of its interpretation, stating in a footnote that
its rationale “would not apply to an Akins Accelerator”
because “a shooter using an Akins Accelerator need
only pull the trigger once to activate the firing sequence.” App., infra, 27a n.8. That distinction is illusory. As explained above, the bump stock designs at issue here also require only a single “pull [of ] the trigger”
24
to activate the continuous firing sequence. Ibid. The
only arguable difference is that the Akins Accelerator
contained a mechanical spring that obviated any need
for the shooter to maintain forward pressure on the
front of the gun with the non-shooting hand—a distinction that ATF previously found relevant to assessing
whether a device enables firing multiple shots “automatically,” but one that has nothing to do with how
many times the trigger mechanically resets during the
continuous firing cycle.
b. The plurality’s treatment of “automatically” was
similarly flawed. See App., infra, 28a-31a. The plurality accepted that “automatically” means “ ‘self-acting,’ ”
id. at 28a, but reasoned that a bump stock does not enable continuous firing through a self-acting mechanism
because the shooter must “maintain manual, forward
pressure on the barrel” with the non-trigger hand, id.
at 29a. The plurality acknowledged that a conventional
machinegun also “requires sustained input” (holding
down the trigger) in order to fire automatically. Id. at
30a. But it viewed the forward pressure required with
bump stocks as different because the pressure is not exerted on the trigger itself. See ibid. (stating that “the
act of pulling and holding the trigger is one function”).
Accepting that distinction would create an enormous
and implausible loophole in the statute. On the plurality’s view, a fully automatic rifle would cease to be a
statutory “machinegun” if it were modified to require
the shooter to also press and hold a button with his nontrigger hand in order to fire continuously. 26 U.S.C.
5845(b). So modified, the weapon would not fire more
than one shot “automatically,” under the plurality’s approach, because the continuous firing sequence would
require sustained input from the shooter beyond merely
25
holding the trigger. The plurality’s view would thus “allow gun manufacturers to circumvent Congress’s longtime ban on machineguns by designing parts specifically intended to achieve machinegun functionality with
a single pull of the trigger so long as the part also requires some minutia of human involvement” beyond
holding the trigger. Gun Owners of Am., Inc. v. Garland, 19 F.4th 890, 910 (6th Cir. 2021) (opinion of Gibbons, J.), cert. denied, 143 S. Ct. 83 (2022).
That cannot be correct. Congress did not ban all new
machineguns only to allow the ban to be circumvented
by a trivial shift in the locus of the shooter’s pressure
from the trigger to the fore-grip, the barrel, a button,
or any other similar contrivance. Instead, the modified
automatic weapon described above would qualify as a
machinegun for precisely the same reason as a rifle with
a bump stock: A single function of the trigger initiates
an automatic sequence of firing more than one shot,
even though one condition for that firing sequence to
continue is sustained pressure by the shooter’s other
hand. The discharge of multiple shots after a single
trigger pull occurs as the result of the “self-acting”
mechanism of the device itself and therefore happens
“automatically.” 83 Fed. Reg. at 66,519.
c. A majority of the en banc court did not endorse
the plurality’s understanding of “single function of the
trigger” and “automatically,” but nonetheless concluded that “lenity” requires reading those terms not to
encompass bump stocks. App., infra, 2a n*. The majority stated that “assuming arguendo that those two
provisions [in the statutory definition] are indeed ambiguous,” the rule of lenity applied because the majority
was “unable to resolve either of the ties” that it perceived in evaluating the parties’ competing interpreta-
26
tions. Id. at 43a. The majority further stated that its
inability to “resolve * * * the ties” was a sufficient basis
“to conclude that this statute—and for purposes of this
case, only this statute—is grievously ambiguous.” Ibid.
The court of appeals’ inability to form a majority endorsing a particular reading of the statutory definition
is not itself a sound basis for applying lenity. This Court
has explained that the rule of lenity comes into play
when interpreting a criminal statute only when, “after
considering text, structure, history, and purpose, there
remains a grievous ambiguity or uncertainty in the statute such that the Court must simply guess as to what
Congress intended.” Maracich v. Spears, 570 U.S. 48,
76 (2013) (quoting Barber v. Thomas, 560 U.S. 474, 488
(2010)); accord Liparota v. United States, 471 U.S. 419,
427 (1985). That standard is not met here. To the contrary, as demonstrated above, application of the ordinary tools of statutory construction yields a firm conclusion that bump stocks are “machineguns.”
B. The Decision Below Creates An Acknowledged Circuit
Conflict
In holding that lenity compels reading the definition
of “machinegun” not to encompass bump stocks, the
Fifth Circuit acknowledged that three other federal circuits had rejected analogous challenges to the same
ATF rule. App., infra, 16a-17a; cf. id. at 71a (Higginson, J., dissenting) (noting the same conflict). Those
decisions rested on a variety of grounds, but they all
reached the same bottom-line conclusion of declining to
invalidate or enjoin the rule. See Gun Owners of Am.,
Inc., 19 F.4th at 896 (6th Cir.) (affirming, by an equally
divided vote of the en banc court, district court’s order
denying preliminary injunction); Aposhian v. Barr, 958
F.3d 969, 984-989 (10th Cir.) (affirming denial of prelim-
27
inary injunction), vacated on reh’g, 973 F.3d 1151 (10th
Cir. 2020), reinstated, 989 F.3d 890 (10th Cir. 2021),
cert. denied, 143 S. Ct. 84 (2022); Guedes v. ATF, 920
F.3d 1, 28-32 (D.C. Cir. 2019) (per curiam) (Guedes I)
(affirming denial of preliminary injunction), cert. denied, 140 S. Ct. 789 (2020).
In addition to the decisions identified by the Fifth
Circuit, the D.C. Circuit also held that ATF’s final rule
“is consistent with the best interpretation of ‘machine
gun’ under the governing statutes” in Guedes II, which
involved an appeal from a final judgment in the same
litigation in which the D.C. Circuit had previously affirmed the denial of a preliminary injunction. See
Guedes II, 45 F.4th at 310. Notably, the D.C. Circuit
reached that conclusion without relying on “the Chevron framework,” id. at 313, which had been applied in
earlier challenges. See Guedes I, 920 F.3d at 28;
Aposhian, 958 F.3d at 984; see also Chevron U.S.A. Inc.
v. NRDC, Inc., 467 U.S. 837, 842-845 (1984). The D.C.
Circuit instead recognized that ATF had identified “the
best reading” of the definition “in light of the plain language and purpose of the statute.” Guedes II, 45 F.4th
at 314. The D.C. Circuit also rejected the same interpretation of “single function of the trigger” that the plurality endorsed here, explaining that reading that
phrase to “refer[] to the mechanical action of the trigger ” would be “unworkable, internally inconsistent, and
counterintuitive.” Id. at 319-320. And the D.C. Circuit
declined to apply lenity for reasons that should have
foreclosed resorting to lenity here as well. See id. at
322 (observing that the statute contains no grievous am-
28
biguity given the “array of tools” supporting ATF’s interpretation).3
The government previously urged this Court to deny
petitions for writs of certiorari seeking further review
of judgments upholding ATF’s final rule, and the Court
did so. See Aposhian v. Garland, 143 S. Ct. 84 (2022)
(No. 21-159); Gun Owners of Am., Inc. v. Garland, 143
S. Ct. 83 (2022) (No. 21-1215); Guedes v. ATF, 140 S. Ct.
789 (2020) (No. 19-296). But the Fifth Circuit’s decision
materially alters the legal landscape by creating an
acknowledged circuit split. And the precedential effect
of the decision below is likely to effectively “legalize”
bump stocks in a large portion of the United States.
App., infra, 71a (Higginson, J., dissenting). Even if the
interpretive rule itself is not enjoined or vacated, any
future criminal prosecution brought within the Fifth
Circuit on the theory that bump stocks are machineguns
would be fatally undercut by the holding of the decision
below. This Court’s review is therefore necessary to restore uniformity to federal law.
By contrast, the U.S. Navy-Marine Corps Court of Criminal Appeals held in United States v. Alkazahg, 81 M.J. 764 (2021), that
bump stocks do not satisfy the definition of “machinegun” in Section
5845(b) and that a servicemember’s possession of such a device
therefore did not violate the Uniform Code of Military Justice, see
id. at 784. In addition, the question whether bump stocks are machineguns is currently pending before a panel of the Sixth Circuit.
See Hardin v. ATF, No. 20-6380 (argued Jan. 19, 2023). The question is also implicated by an appeal that is currently stayed in the
Federal Circuit, Codrea v. Garland, No. 21-1707, which arises from
the same consolidated proceedings as the appeal to the D.C. Circuit
in Guedes II. See Br. in Opp. at 20 & n.3, McCutchen v. United
States, 143 S. Ct. 422 (2022) (No. 22-25).
3
29
C. The Question Presented Is Exceptionally Important,
And This Case Is A Suitable Vehicle
The question presented is exceptionally important
for federal law enforcement and public safety. Congress has long regulated machineguns because of their
“destructive potential and exacerbation of serious
crime.” Guedes II, 45 F.4th at 316. Rifles equipped
with bump stocks not only satisfy the statutory definition of “machinegun” but also, as a practical matter,
present the same “heightened capacity for lethality.”
Ibid. Like other machineguns, rifles modified with
bump stocks are capable of firing hundreds of bullets
per minute. The Las Vegas mass shooter, for example,
“was able to fire several hundred rounds of ammunition
in a short period of time” using bump stocks, “killing 58
people and wounding approximately 500” in a matter of
minutes. 83 Fed. Reg. at 66,516.
If the decision below is allowed to stand, its consequences are likely to reverberate nationwide. Under
the National Firearms Act, persons engaged in the
manufacture of machineguns (e.g., for lawful sales to
governmental entities, including the armed forces) are
required to register and pay a special tax, 26 U.S.C.
5801-5802; to register the making of each machinegun,
26 U.S.C. 5822; and to assign each machinegun a unique
serial number, 26 U.S.C. 5842(a). Serializing the weapons assists in tracing them in the event one is used in a
crime. The decision below, however, is likely to mean
that manufacturers within the Fifth Circuit will be able
to make and sell bump stocks to individuals without
background checks and without registering or serializing the devices. Given the nationwide traffic in firearms, there is little reason to believe that such devices
will remain confined to the Fifth Circuit.
30
Finally, this case is an appropriate vehicle. The case
arises from a final judgment after a bench trial, and it
squarely presents a question of statutory interpretation. Prior petitions addressing ATF’s final rule have
asked the Court to resolve various matters of administrative law, such as whether Chevron may be “waived.”
See Guedes, 140 S. Ct. at 789-791 (statement of Gorsuch, J.). Those ancillary matters are not at issue here.
The government maintains only that bump stocks are
machineguns under the best interpretation of the statute. The Fifth Circuit erred in holding otherwise, and
this Court should grant review and reverse.
CONCLUSION
The petition for a writ of certiorari should be
granted.
Respectfully submitted.
ELIZABETH B. PRELOGAR
Solicitor General
BRIAN M. BOYNTON
Principal Deputy Assistant
Attorney General
BRIAN H. FLETCHER
Deputy Solicitor General
MATTHEW GUARNIERI
Assistant to the Solicitor
General
MARK B. STERN
MICHAEL S. RAAB
ABBY C. WRIGHT
BRAD HINSHELWOOD
Attorneys
APRIL 2023
APPENDIX
TABLE OF CONTENTS
Page
Appendix A
— Court of appeals en banc opinion
(Jan. 6, 2023) ............................................... 1a
Appendix B — Court of appeals panel opinion
(Dec. 14, 2021)............................................ 72a
Appendix C — District court findings of fact and
conclusions of law (Nov. 23, 2020) ........... 92a
Appendix D — Court of appeals order granting
rehearing (June 23, 2022) ...................... 154a
Appendix E — Statutory and regulatory provisions:
18 U.S.C. 921(a)(24) .......................................................... 156a
18 U.S.C. 922(o) ................................................................ 156a
26 U.S.C. 5845(b) .............................................................. 156a
27 C.F.R. 447.11 ................................................................ 157a
27 C.F.R. 478.11 ................................................................ 158a
27 C.F.R. 479.11 ................................................................ 159a
APPENDIX A
UNITED STATES COURT OF APPEALS
FOR THE FIFTH CIRCUIT
No. 20-51016
MICHAEL CARGILL, PLAINTIFF-APPELLANT
v.
MERRICK GARLAND, IN HIS OFFICIAL CAPACITY AS
U.S. ATTORNEY GENERAL; UNITED STATES
DEPARTMENT OF JUSTICE; STEVEN DETTELBACH,
IN HIS OFFICIAL CAPACITY AS DIRECTOR OF THE
BUREAU OF ALCOHOL, TOBACCO, FIREARMS , AND
EXPLOSIVES ; BUREAU OF ALCOHOL, TOBACCO,
FIREARMS , AND EXPLOSIVES ,
DEFENDANTS -APPELLEES
[Filed:
Jan. 6, 2023]
Appeal from the United States District Court
for the Western District of Texas
USDC No. 1:19-CV-349
Before: RICHMAN, Chief Judge, and JONES, SMITH,
STEWART, DENNIS, ELROD, SOUTHWICK, HAYNES,
GRAVES, HIGGINSON, WILLETT, HO, DUNCAN, ENGELHARDT, OLDHAM, and WILSON, Circuit Judges.
JENNIFER WALKER ELROD, Circuit Judge, joined by
RICHMAN, Chief Judge, and JONES, SMITH, STEWART,
(1a)
2a
SOUTHWICK, HAYNES, WILLETT, HO, DUNCAN, ENGEL*
HARDT, OLDHAM, and WILSON, Circuit Judges:
Since the National Firearms Act of 1934, federal law
has heavily regulated machineguns. Indeed, as proposed, that law was known to many as “the AntiMachine Gun Bill.” The possession or transfer of a machinegun was eventually banned through the Gun Control Act of 1968 and the Firearms Owners’ Protection
Act of 1986. Today, possession of a machinegun is a
federal crime, carrying a penalty of up to ten years’ incarceration.
This appeal concerns a regulation promulgated by
the federal Bureau of Alcohol, Tobacco, Firearms, and
Explosives, purporting to interpret the federal prohibition on machineguns as extending to bump stocks. A
bump stock is a firearm attachment that allows a shooter
to harness the natural recoil of a semi-automatic weapon
to quickly re-engage the trigger after firing, enabling
him to shoot at an increased rate of speed. When ATF
first considered the type of bump stocks at issue here, it
*
Of the sixteen members of our court, thirteen of us agree that an
act of Congress is required to prohibit bump stocks, and that we
therefore must reverse. Twelve members (CHIEF JUDGE RICHMAN and JUDGES JONES, SMITH, STEWART, ELROD, SOUTHWICK,
HAYNES, WILLETT, HO, DUNCAN, ENGELHARDT, and WILSON) reverse on lenity grounds. Eight members (JUDGES JONES, SMITH,
ELROD, WILLETT, DUNCAN, ENGELHARDT, OLDHAM, and WILSON)
reverse on the ground that federal law unambiguously fails to cover
non-mechanical bump stocks.
CHIEF JUDGE RICHMAN, JUDGE STEWART, and JUDGE SOUTHWICK concur in the judgment and join in Part V, as does JUDGE HO,
who also writes separately. JUDGE OLDHAM concurs in the judgment and joins in Parts I-IV.A. JUDGE HAYNES only concurs in the
judgment and writes separately.
3a
understood that they were not machineguns. ATF
maintained this position for over a decade, issuing many
interpretation letters to that effect to members of the
public.
But ATF reversed its longstanding position in 2018,
subjecting anyone who possessed a bump stock to criminal liability. ATF reversed its position to a great extent in response to the tragic events that occurred in Las
Vegas on October 1, 2017. On that day, a deranged
gunman murdered dozens of innocent men and women,
and injured hundreds more. To carry out this appalling crime, the gunman used many weapons and utilized
many accessories—including bump stocks.
Public pressure to ban bump stocks was tremendous.
Multiple bills to that effect were introduced in both
houses of Congress. But before they could be considered in earnest, ATF published the regulation at issue
here, short-circuiting the legislative process. Appellant Michael Cargill surrendered several bump stocks to
the Government following publication of the regulation
at issue. He now challenges the legality of that regulation, arguing that a bump stock does not fall within the
definition of “machinegun” as set forth in federal law,
and thus that ATF lacked the authority to issue a regulation purporting to define the term as such.
Cargill is correct. A plain reading of the statutory
language, paired with close consideration of the mechanics of a semi-automatic firearm, reveals that a bump
stock is excluded from the technical definition of “machinegun” set forth in the Gun Control Act and National
Firearms Act.
4a
But even if that conclusion were incorrect, the rule of
lenity would still require us to interpret the statute
against imposing criminal liability. A rich legal tradition supports the “well known rule” that “penal laws are
to be construed strictly.” United States v. Wiltberger,
18 U.S. (5 Wheat.) 76, 94-95 (1820). As Chief Justice
Marshall explained long ago, the rule “is founded on the
tenderness of the law for the rights of individuals; and
on the plain principle that the power of punishment is
vested in the legislative, not in the judicial department.
It is the legislature, not the Court, which is to define a
crime, and ordain its punishment.” Id. at 95.
The Government’s regulation violates these principles. As an initial matter, it purports to allow ATF—
rather than Congress—to set forth the scope of criminal
prohibitions. Indeed, the Government would outlaw
bump stocks by administrative fiat even though the very
same agency routinely interpreted the ban on machineguns as not applying to the type of bump stocks at
issue here. Nor can we say that the statutory definition unambiguously supports the Government’s interpretation. As noted above, we conclude that it unambiguously does not. But even if we are wrong, the statute is at least ambiguous in this regard. And if the
statute is ambiguous, Congress must cure that ambiguity, not the federal courts.
The definition of “machinegun” as set forth in the National Firearms Act and Gun Control Act does not apply
to bump stocks. And if there were any doubt as to this
conclusion, we conclude that the statutory definition is
ambiguous, at the very least. The rule of lenity therefore compels us to construe the statute in Cargill’s favor.
Either way, we must REVERSE.
5a
I
A
The Gun Control Act of 1968 provides that “it shall
be unlawful for any person to transfer or possess a machinegun.” 18 U.S.C. § 922(o)(1). The Act defines
machinegun as follows:
The term “machinegun” means any weapon which
shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot,
without manual reloading, by a single function of the
trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts
designed and intended, for use in converting a
weapon into a machinegun, and any combination of
parts from which a machinegun can be assembled if
such parts are in the possession or under the control
of a person.
26 U.S.C. § 5845(b); see 18 U.S.C. § 921(a)(24) (incorporating the definition in the National Firearms Act).
The traditional example of a machinegun 1 is a rifle
capable of automatic fire, like the M-16.
Semiautomatic rifles like the AR-15 are not machineguns.
See Hollins v. Lynch, 827 F.3d 436, 440 n.2 (5th Cir.
2016) (The M-16 “is capable of automatic fire, that is to
say, firing more than one round per trigger-action.
. . . The AR-15 is essentially a semi-automatic version
of the M-16, that is to say, it fires only one round per
trigger-action.”).
We spell machinegun as being one word because that is how Congress has defined the term in the statutes at issue here.
1
6a
B
To understand what a machinegun is, it is helpful to
understand what a machinegun is not. To that end, the
firing mechanism of a semi-automatic weapon is especially important. The relevant parts are as follows:
The trigger is the interface between the gun’s internal mechanism and the human finger. The sear is the
trigger’s top-forward geometric plane, which locks
snugly into a groove near the spring of the hammer.
The hammer is the spring-loaded element that strikes
the firing pin, causing ignition of the charge and propulsion of the bullet. The disconnector is a part that sits
on top of the trigger and serves to reset the hammer after a round is fired; this resetting is what makes a semiautomatic weapon semi-automatic.
The mechanics of the firing process are as follows.
First, the user pulls the trigger. Doing so disengages
7a
the hammer from the sear, allowing the spring to swing
the hammer to strike the firing pin, which causes the
charge to combust and propel the bullet. The firing of
the bullet thrusts the bolt backward, which kicks the
hammer into the disconnector on top of the stilldepressed trigger. When the trigger is reset, the hammer is pulled back into the cocked position and secured
by the trigger’s sear as it slips off the disconnector.
The user may then fire again by pulling the trigger,
without having to manually re-cock the hammer. The
mechanics are viewed below: 2
The end result is that the user of a semi-automatic
firearm can fire rapidly by means of repeated use of the
trigger. Critically, use of the trigger necessarily corThis figure is a stationary image taken from an animated graphic
that moves to display the relevant motion. The moving image may
be found here: https://www.ca5.uscourts.gov/opinions/pub/20/2051016_ar15.gif
2
8a
responds one-to-one with bullets fired. That is, a single pull of the trigger results in a single bullet fired.
Without resetting the trigger, the disconnector cannot
reset the hammer to the fully cocked position. And unless the hammer is fully cocked, it will not be able to
strike the firing pin with sufficient force to discharge the
weapon a second time. (When a weapon fails to fire for
this reason, it is said to experience a “hammer follow”
malfunction.)
In sum, both the hammer and the
trigger-disconnector must invariably return full circle
before another round can be dispatched.
This process may be contrasted with a fully automatic gun, which is equipped with something called an
“auto sear”—a device that serves to re-cock and release
the hammer in tandem with the motion of the bolt for so
long as the trigger remains depressed. In other words,
the auto sear enables a pendulum swing of the hammer
in sync with the bolt without any further input from the
user; with one pull of the trigger, an automatic weapon
can shoot continuously until ammunition is depleted.
C
The statutory definition of a machinegun also includes devices that convert an ordinary firearm into a
machinegun. See United States v. Camp, 343 F.3d 743
(5th Cir. 2003) (holding that a switch—which, if flipped,
would cause a semi-automatic rifle to fire continuously—is a device that turns an ordinary firearm into a
machinegun). The issue presented here is whether a
bump stock is such a device.
A bump stock is an accessory that attaches to a semiautomatic weapon and assists the shooter to engage in
bump firing. Bump firing, in turn, is a technique
9a
whereby a shooter uses a firearm’s natural recoil to
quickly reengage the trigger, resulting in an increased
rate of fire. It is possible to bump fire an ordinary
semi-automatic rifle without any assisting device, but a
bump stock makes the technique easier.
A typical bump stock consists of a sliding shoulder
stock molded to a grip, a trigger ledge where the shooter
places his finger, and a detachable rectangular receiver
module that goes into the receiver well of the bump
stock’s handle to guide the recoil of the weapon when
fired. To begin bump firing, the shooter presses forward on the firearm’s forebody to bump into the trigger
finger. The gun then slides back and forth, and the recoil energy forces the gun backward, re-engaging the
trigger. The shooter maintains forward pressure on
the gun’s forebody, again causing the trigger to bump
10a
into the trigger finger, maintaining fire.
process may be viewed as follows: 3
The firing
In summary, a bump stock combines with a semiautomatic weapon to facilitate the repeated function of
the trigger. To be sure, it makes the process faster and
easier. But the mechanics remain exactly the same:
the firing of each and every round requires an intervening function of the trigger. This does not alter the form
of manual input that the user must provide to discharge
the weapon. Without a bump stock or the use of an alternative bump technique, the user must provide manual input by pulling the trigger with the muscles of his
trigger finger. With a bump stock, the shooter need
not pull and release his trigger finger. But the shooter
must still apply forward pressure to the weapon’s forebody in order to maintain the shooting mechanism.
Again, the manual input remains, even though its form
changes.
We note one important distinction. Some bump
stocks—called mechanical bump stocks—are equipped
with springs or other internal mechanical devices that
automatically assist the shooter to engage in bump firing. For such a bump stock, the shooter does not have
to maintain pressure on the barrel and trigger ledge in
order to maintain this firing sequence. Only nonmechanical bump stocks are at issue in this case.
This figure is a stationary image taken from an animated graphic
that moves to display the relevant motion. The moving image may
be found here: https://www.ca5.uscourts.gov/opinions/pub/20/2051016_bump_fire_animation.gif
3
11a
D
Bump stocks were first invented in the early 2000s.
Historically, ATF distinguished between mechanical
and non-mechanical bump stocks in categorizing a particular accessory as a machinegun. This categorization
is done through ATF’s Firearms Technology Branch,
which is authorized to issue classification letters upon
request from members of the public. See 26 U.S.C.
§ 5841(c) (requiring firearm manufacturers and possessor to receive “authorization”); Bureau of Alcohol, Tobacco, Firearms and Explosives, National Firearms
Handbook § 7.2.4 (setting forth the classification process). When ATF first considered mechanical bump
stocks in 2006, it categorized them as machineguns:
“[A] device attached to a semiautomatic firearm that
uses an internal spring to harness the force of a firearm’s recoil so that the firearm shoots more than one
shot with a single pull of the trigger is a machinegun.”
83 Fed. Reg. at 66514. ATF maintains that categorization.
But from the time ATF first considered nonmechanical bump stocks to 2017, it categorized that type
of bump stock as not being a machinegun. In that time,
the Firearms Technology Branch issued dozens of classification letters regarding non-mechanical bump
stocks, each time arriving at the same conclusion. One
letter from 2010 is illustrative:
Dear [Applicant], This is in reference to your submission . . . asking for an evaluation of a replacement shoulder stock for an AR-15 type rifle. Your
letter advises that the stock (referenced in this reply
as a “bump-stock”) is intended to assist persons
whose hands have limited mobility to “bump-fire” an
12a
AR-15 type rifle. . . . The stock has no automatically functioning mechanical parts or springs and
performs no automatic mechanical function when installed. In order to use the installed device, the
shooter must apply constant forward pressure with
the non-shooting hand and constant rearward pressure with the shooting hand. Accordingly, we find
that the “bump-stock” is a firearm part and is not
regulated as a firearm under the Gun Control Act or
the National Firearms Act.
However, bump-stock classification reached a point
of inflection on October 1, 2017. On that day, a gunman
murdered over 50 innocent men and women in Las Vegas, and injured 500 more. He used several weapons,
many of which were equipped with extended magazines
and bump stocks. These tragic events thrust bump
stocks into the center of national attention.
Within ten days of the shooting, two bills prohibiting
bump-stock devices were proposed in Congress. See
Automatic Gunfire Prevention Act, H.R. 3947, 115th
Cong. (2017)4; To Amend Title 18, United States Code,
To Prohibit the Manufacture, Possession, or Transfer
of Any Part or Combination of Parts That is Designed
and Functions to Increase the Rate of Fire of a Semiautomatic Rifle, H.R. 3999, 115th Cong. (2017). While
Congress debated the bills, ATF published a notice of
proposed rulemaking, intending to reverse its previous
interpretation that non-mechanical bump stocks are not
machineguns for purposes of the National Firearms Act
and Gun Control Act. Notice of Proposed Rulemaking,
Bump-Stock-Type Devices, 83 Fed. Reg. 13442 (Mar. 29,
An identical bill was proposed in the Senate.
fire Prevention Act, S. 1916, 115th Cong. (2017).
4
Automatic Gun-
13a
2018). Senator Diane Feinstein—who sponsored one
of the bills mentioned above—expressed concern with
the proposed rule:
Until today, the ATF has consistently stated that
bump stocks could not be banned through regulation
because they do not fall under the legal definition of
a machine gun.
Now, the department has done an about face, claiming that bump stocks do fall under the legal definition
of a machine gun and it can ban them through regulations. The fact that ATF said as recently as April
2017 that it lacks this authority gives the gun lobby
and its allies even more reason to file a lawsuit to
block the regulations.
Unbelievably, the regulation hinges on a dubious
analysis claiming that bumping the trigger is not the
same as pulling it. The gun lobby and manufacturers will have a field day with this reasoning. What’s
more, the regulation does not ban all devices that accelerate a semi-automatic weapon[’]s rate of fire to
that of a machine gun.
Both Justice Department and ATF lawyers know
that legislation is the only way to ban bump stocks.
The law has not changed since 1986, and it must be
amended to cover bump stocks and other dangerous
devices like trigger cranks. Our bill does this—the
regulation does not.
Press Release, Sen. Dianne Feinstein, Feinstein Statement on Regulation to Ban Bump Stocks (Mar. 23,
2018). ATF continued with the rulemaking process,
publishing the final rule later that year. Final Rule,
Bump-Stock-Type Devices, 83 Fed. Reg. 66514 (Dec. 26,
14a
2018).5 The Final Rule purported to modify the definition of machinegun as follows:
A “machinegun,” “machine pistol,” “submachinegun,” or “automatic rifle” is a firearm which
shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot,
without manual reloading, by a single function of the
trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts
designed and intended, for use in converting a
weapon into a machinegun, and any combination of
parts from which a machinegun can be assembled if
such parts are in the possession or under the control
of a person. For purposes of this definition, the
term “automatically” as it modifies “shoots, is designed to shoot, or can be readily restored to shoot,”
means functioning as the result of a self-acting or
selfregulating mechanism that allows the firing of multiple rounds through a single function of the trigger;
and “single function of the trigger” means a single
pull of the trigger and analogous motions. The term
“machinegun” includes a bump-stock-type device,
i.e., a device that allows a semi-automatic firearm to
shoot more than one shot with a single pull of the trigger by harnessing the recoil energy of the semiautomatic firearm to which it is affixed so that the
Acting Attorney General Matthew Whitaker initially signed the
Final Rule, but some questioned his authority to do so. In response, Attorney General William Barr ratified the Final Rule upon
his being sworn into office. 84 Fed. Reg. 9239 (Mar. 14, 2019).
5
15a
trigger resets and continues firing without additional
physical manipulation of the trigger by the shooter.
83 Fed. Reg. at 66553-54.
E
Plaintiff Michael Cargill lawfully acquired two nonmechanical bump stocks but surrendered them to ATF
after passage of the Final Rule. He then sued ATF and
other federal defendants, bringing several claims under
the Administrative Procedure Act. First, he contends
that ATF lacked authority to promulgate the Final Rule
because its interpretation of machinegun conflicts with
the unambiguous statutory definition. And even if the
statute is ambiguous, Cargill says, it should be construed in his favor because of the rule of lenity. And
because the statute concerns criminal penalties, the
Government’s interpretation is not entitled to deference
under Chevron USA, Inc. v. Natural Resources Defense
Council, Inc., 467 U.S. 837 (1984). Cargill also argues
that the Final Rule constitutes an unconstitutional exercise of legislative power by an administrative agency.
After a one-day bench trial, the district court entered
judgment for the Government. Cargill v. Barr, 502 F.
Supp. 3d 1163 (W.D. Tex. 2020). It declined to apply
Chevron but found that the Government’s new interpretation of machinegun is the best reading of the relevant
statute. The district court also rejected Cargill’s nondelegation claim. A panel of this court affirmed, concluding that the Final Rule’s interpretation of machinegun is the best reading of the statute, and declining
to reach Chevron or the nondelegation question. Cargill v. Garland, 20 F.4th 1004 (5th Cir. 2021). We
16a
granted rehearing en banc, vacating the panel opinion.
37 F.4th 1091.
II
Three of our sister circuits have reviewed preliminary-injunction motions relating to the Final Rule.
The issues engendered great disagreement, but each
circuit that has addressed them agrees that the definition of machinegun within the National Firearms Act
and Gun Control Act does not unambiguously mean
what the Government says it means. Each circuit ultimately denied preliminary injunctive relief, and the Supreme Court denied each of the certiorari petitions.
See, e.g., Guedes v. ATF, 140 S. Ct. 789, 791 (2020) (Gorsuch, J., statement respecting denial of certiorari) (“Despite these concerns, I agree with my colleagues that the
interlocutory petition before us does not merit review.”).
A divided D.C. Circuit panel determined that the Final Rule is ambiguous, but applied Chevron deference to
the Government’s statutory interpretation. Guedes v.
ATF, 920 F.3d 1 (D.C. Cir. 2019). The dissent contended that the Final Rule contradicts the statute’s
plain meaning. Id. at 35 (Henderson, J., concurring in
part and dissenting in part). Although the Supreme
Court denied certiorari, 140 S. Ct. 789 (2020), one Justice wrote separately to explain his view that Chevron
does not apply because (i) the Government had expressly waived its application, (ii) it does not apply to
regulations bearing criminal sanctions, and (iii) the Final Rule directly contradicts the Government’s previous
interpretation. Id. at 789-91 (Gorsuch, J., statement
respecting denial of certiorari).
17a
In another divided opinion, the Tenth Circuit reached
the same conclusion as the D.C. Circuit: that the Final
Rule was ambiguous and entitled to Chevron deference.
Aposhian v. Barr, 958 F.3d 969 (10th Cir. 2020); see id.
at 991 (Carson, J., dissenting). The court initially
granted rehearing en banc, vacating the panel decision,
973 F.3d 1151 (10th Cir. 2020) (en banc), but later vacated the order as improvidently granted, reinstating
the former opinion. Aposhian v. Wilkinson, 989 F.3d
890 (10th Cir. 2021) (en banc), cert denied sub nom.
Aposhian v. Garland, 143 S. Ct. 83 (2022). Three dissents were written, each of which was joined by five of
the eleven participating judges.
The first dissent
would have held that (i) the statute unambiguously does
not apply to bump stocks, (ii) Chevron does not apply
either because the Government waived it or because it
does not apply in the criminal context, and (iii) the Final
Rule may violate nondelegation principles. Id. at 891903 (Tymkovich, C.J., dissenting); see also id. at 903-04
(Hartz, J., dissenting); id. at 904-06 (Eid, J., dissenting);
id. at 906-08 (Carson, J., dissenting).
Finally, in yet another divided opinion, a Sixth Circuit panel ruled against the Government, declining to
apply Chevron deference and holding the statutory definition of machinegun does not include bump stocks.
Gun Owners of America, Inc. v. Garland, 992 F.3d 446,
450 (6th Cir. 2021); but see id. at 475-92 (White, J., dissenting) (arguing that Chevron applies and that the Government’s interpretation is reasonable). The court
granted rehearing en banc, 2 F.4th 576 (6th Cir. 2021)
(en banc), and an evenly-divided court affirmed the district court’s denial of the preliminary injunction. 19
F.4th 890 (6th Cir. 2020), cert denied, 143 S. Ct. 83
(2022).
18a
In addition to these circuit decisions, the NavyMarine Corps Court of Criminal Appeals considered the
Final Rule in the context of a criminal prosecution for
possession of a machinegun. See United States v.
Alkazahg, 81 M.J. 764, 780-81 (N-M. Ct. Crim. App.
2021). That court determined that, under the best
reading of the statutory language, a bump stock is not a
machinegun. But it ultimately found that the statute is
ambiguous and applied the rule of lenity to construe the
statute against imposing criminal liability.
It dismissed the charge for possession of a machinegun.
III
Our primary task is to interpret the meaning of machinegun as defined in 26 U.S.C. § 5845(b). Of course,
the Government has sponsored its own interpretation,
as expressed in the Final Rule. Ordinarily, that action
would invoke the two-step Chevron framework. As we
recently summarized, “[a]t step one, we ask whether
Congress has directly spoken to the precise question at
issue, in which case we must give effect to the unambiguously expressed intent of Congress and reverse an
agency’s interpretation that fails to conform to the statutory text.” Huawei Technologies USA, Inc. v. FCC, 2
F.4th 421, 433 (5th Cir. 2021) (quotations omitted).
But here, the Government has declined to invoke
Chevron in any of the lawsuits challenging the Final
Rule. Nonetheless, several circuits have applied Chevron deference to challenges of the Final Rule, and so we
will consider Chevron’s applicability below. But before
we do, we determine the statute’s meaning using traditional statutory-interpretation tools. That is, “the oldfashioned way.” Guedes, 140 S. Ct. at 790 (Gorsuch, J.,
statement respecting denial of certiorari); see also
19a
Guedes, 920 F.3d at 42 (Henderson, J., concurring in
part and dissenting in part); Aposhian, 989 F.3d at 898
(Tymkovich, C.J., dissenting). If the statute is unambiguous, it does not matter whether Chevron applies.
See, e.g., Western Refining Southwest, Inc. v. FERC,
636 F.3d 719, 727 (5th Cir. 2011) (“[If] the statute’s text
is unambiguous, we need not proceed to Step Two of
Chevron.”).
Recall that in this circumstance, Congress has defined machinegun to mean “any weapon which shoots
. . . automatically more than one shot . . . by a
single function of the trigger,” or any accessory that allows a firearm to shoot in that manner. 26 U.S.C.
§ 5845(b). The parties dispute whether the fire created
by a semi-automatic rifle equipped with a nonmechanical bump stock is produced both “automatically” and “by single function of the trigger.” We address those components in reverse order. 6
Cargill also argues that the Final Rule is void because it is a legislative rule—as opposed to an interpretive rule—and because relevant federal law does not authorize ATF to issue such a rule. We
assume arguendo that the Final Rule is legislative in nature and that
ATF is authorized to issue such a rule. First, if the rule were interpretive in nature, it would not be eligible for Chevron deference.
United States v. Mead Corp., 533 U.S. 218, 232 (2001). But as explained infra, three independent reasons demand that we not defer
to the Government here. Second, if ATF were not authorized to
promulgate legislative rules, the rule at issue would be void. Ultimately, however, we conclude that the Government’s interpretation
is inconsistent with the statutory definition, so ATF lacked authority
to issue the Final Rule. We therefore need not consider Cargill’s
additional argument that the Final Rule is a legislative rule.
6
20a
A
The first phrase we consider is “by a single function
of the trigger.” At the time the statute was passed,
“function” meant “action.” Webster’s New International Dictionary 1019 (2d ed. 1934); see Guedes, 920
F.3d at 43 (Henderson, J., concurring in part and dissenting in part); Aposhian, 989 F.3d at 895 (Tymkovich,
C.J., dissenting).
Thus, the relevant question is
whether a semi-automatic rifle equipped with a non-mechanical bump stock fires more than one shot each time
the trigger “acts.”
It does not. As illustrated above, a semi-automatic
weapon utilizes a simple mechanical process: the trigger disengages the hammer from the sear, the hammer
strikes the firing pin, the bullet fires, and the recoil
pushes the hammer against the disconnector, which resets the trigger. This process happens every single
time one bullet is fired. To be sure, a non-mechanical
bump stock increases the rate at which the process occurs. But the fact remains that only one bullet is fired
each time the shooter pulls the trigger.
The Government contends that “single function of
the trigger” means “a single pull of the trigger and analogous movements.” 83 Fed. Reg. at 66553. That is,
according to the Government, “function” means “pull.”
But that argument fails on its face because a shooter still
pulls the trigger of a semi-automatic weapon equipped
with a non-mechanical bump stock each time he or she
fires a bullet. Without a bump stock, the trigger activates because the shooter flexes his or her finger; with
a bump stock, the trigger activates because the recoil of
the previous shot re-engages the trigger and the
shooter’s maintained force on the gun’s forebody bumps
21a
the trigger against the shooter’s finger. This is a distinction without a difference—the end result in both
cases is that the trigger is pulled. See Guedes, 920 F.3d
at 48 (Henderson, J., concurring in part and dissenting
in part) (“A semiautomatic rifle shoots a single round
per pull of the trigger and the bump stock changes only
how the pull is accomplished.”); Gun Owners of America, 992 F.3d at 469-73, vacated, 2 F.4th 576. Even if
“single function” meant “single pull,” the definition
would still not include a non-mechanical bump stock.
Moreover, even though pulling the trigger can sometimes begin the bump firing sequence, the process is
more typically begun by pushing forward on the forebody of the firearm.
For several of our sister circuits, however, the plain
language is not so plain. They reason that single function of the trigger “could mean ‘a single pull of the trigger from the perspective of the shooter.’ ” Guedes, 920
F.3d at 29; see also Gun Owners of America, 19 F.4th at
905 (White, J., in support of affirmance). Considering
the definition of “function,” one court understood the issue as such: “ [T]hat definition begs the question of
whether ‘function’ requires our focus upon the movement of the trigger, or the movement of the trigger finger. The statute is silent in this regard.” Aposhian,
958 F.3d at 986. According to that logic, for a semiautomatic rifle equipped with a non-mechanical bump
stock, the act of pulling the trigger—which begins the
bump firing sequence—is a single pull for purposes of
the Gun Control Act and National Firearms Act.
The problem with that interpretation is that it is
based on words that do not exist in the statute. The
statute “uses ‘single function of the trigger,’ not single
22a
function of the shooter’s trigger finger.” Guedes, 920
F.3d at 48 (Henderson, J., concurring in part and dissenting in part); see also Aposhian, 989 F.3d at 895
(Tymkovich, C.J., dissenting) (“The statute speaks only
to how the trigger acts, making no mention of the
shooter.”). The Navy-Marine Corps Court of Appeals
likewise refused to read words into the statute:
The best read implies that the shooter initiates the
trigger function by some action, such as pulling the
trigger—or it could be by just pushing a button—and
it is the follow-on action where the trigger acts out its
mechanical design or purpose that speaks to the
“function of the trigger.” The statute does not say
“by a single function of the trigger finger” nor does
it say “by a single pull of the trigger in addition to
external pressure from the shooter’s non-firing
hand.” . . . . Had Congress wanted to use the
phrase “by a single pull of the trigger” for machine
guns, it could have. But it did not.
Alkazahg, 81 M.J. at 780-81.
We agree. The statutory definition of machinegun
utilizes a grammatical construction that ties the definition to the movement of the trigger itself, and not the
movement of a trigger finger. Nor do we rely on grammar alone. Context firmly corroborates what grammar initially suggests by demonstrating that Congress
knew how to write a definition that is keyed to the movement of the trigger finger if it wanted to. But it did
not. The Government offers nothing to overcome this
plain reading, so that we are obliged to conclude that the
statutory definition of machinegun unambiguously
turns on the movement of the trigger and not a trigger
finger.
23a
Grammar rejects a reading based on the shooter’s
perspective. Each component of the statutory definition supports the mechanical perspective, not a
shooter’s perspective. Again, the definition reads as
follows: “[M]achinegun means . . . any weapon
which shoots . . . automatically more than one shot
. . . by a single function of the trigger.” 26 U.S.C.
§ 5845(b). The subject of the sentence, of course, is
machinegun. The linking verb means connects the
subject to the subject complement—weapon. Next,
the adjectival phrase which shoots modifies weapon.
The adverbial phrase automatically more than one shot
then modifies shoots.
Finally, two prepositional
phrases follow. The first, by a single function, modifies the adverbial phrase. The second, of the trigger,
modifies the first prepositional phrase.
See also
Guedes, 920 F.3d at 44 n.13 (Henderson, J., concurring
in part and dissenting in part) (diagramming the statutory definition).
The first thing to note is that the ultimate subject is
machinegun, and the subject complement is weapon.
In other words, a machinegun is defined by reference to
what kind of weapon it is. But identifying the subject
of the sentence is only our first step. We next look, second, to the fact that the term weapon is defined by how
it shoots. So, again, the definition refers to the device
being made to shoot, not the person or thing doing the
shooting. Third, the manner of shooting must be automatic.
Fourth—and critically—the prepositional
phrases define the firing process’s requirements from a
mechanical perspective. The process must occur by a
single function, and the single act must be by the trigger. In short, there is no mention of a shooter. The
grammatical structure continuously points the reader
24a
back to the mechanics of the firearm. The statute does
not care what human input is required to activate the
trigger—it cares only whether more than one shot is
fired each time the trigger acts.
We do not stop with the grammar. With statutes,
“[c]ontext is a primary determinant of meaning. Antonin Scalia & Bryan A. Garner, Reading Law: The Interpretation of Legal Texts 167 (2012). So, we look
next to context for further clues. And context confirms
that the statute must be read from the mechanical perspective. Specifically, context tells us that Congress
knew how to write a definition that explicitly turns on
the action of a shooter rather than the action of a trigger, but chose not to do so here. Immediately following
the definition of machinegun provided in 26 U.S.C.
§ 5845(b), Congress defined the term “rifle” to mean a
weapon designed “to use the energy of the explosive in
a fixed cartridge to fire only a single projectile through
a rifled bore for each single pull of the trigger.”
§ 5845(c) (emphasis added). The statute next defines
“shotgun” to mean a weapon designed “to use the energy of the explosive in a fixed shotgun shell to fire
through a smooth bore either a number of projectiles
(ball shot) or a single projectile for each pull of the trigger.” Id. § 5845(d) (emphases added). “[W]here the
document has used one term in one place, and a materially different term in another, the presumption is that
the different term denotes a different idea.” Reading
Law at 170.
To summarize, the definition of machinegun must
turn on the action (or “function”) of the trigger because
no other actor is mentioned or implied. This conclusion
is only strengthened by the fact that other definitions
25a
within the same statutory provision explicitly turn on
the action of a shooter, showing that Congress knew how
to write a definition that proceeds from a shooter’s perspective, rather than a mechanical one, if it had wanted
to. The notion that the definition turns on the action of
an unnamed shooter is inconsistent with both the grammatical and statutory contexts.
The Government says that this straightforward interpretation defies common sense. It would not have
been prudent for Congress to “zero[] in on the mechanistic movement of the trigger,” the Government says,
because the problem sought to be remedied was “the
ability to drastically increase a weapon’s rate of fire.”
Aposhian v. Barr, 374 F. Supp. 3d 1145, 1152 (D. Utah
2019)). Perhaps Congress’s choice of words was prudent, or perhaps it was not. That is not for us to decide.
But the Government’s objection only accentuates the
fact that Congress did not use words describing the
shooter’s perspective or the weapon’s rate of fire. See
Alkazahg, 81 M.J. at 781 (“Congress could have suggested that a shooter-focused approach or even a rateof-fire approach was the way to read the statute by enacting those words. Even the term ‘machine gun’ suggests a mechanical approach where the shooter interaction is extremely limited.”). Instead, it made up an entirely new phrase—by a single function of the trigger—
that specifically pertains to the mechanics of a firearm.
Prudent or not, Congress defined the term “machinegun” by reference to the trigger’s mechanics. We
are bound to apply that definition as written. 7
Although our reasoning is independently sufficient to support
our conclusion, the application of corpus linguistics only provides
further support. A search in the Corpus of Historical American
7
26a
The Government also points to our decision in United
States v. Camp, arguing that it controls here. 343 F.3d
734. It does not. But to the extent Camp applies, it
supports Cargill’s position. The issue presented in
Camp was whether something other than the metal
lever that ordinarily begins the firing process can be a
“trigger” for purposes of the Gun Control Act and National Firearms Act. The defendant there modified a
semi-automatic rifle, building a switch behind the original trigger that, when pulled, “supplied electrical power
to a motor connected to the bottom of a fishing reel that
had been placed inside the weapon’s trigger guard; the
motor caused the reel to rotate; and that rotation caused
the original trigger to function in rapid succession.”
343 F.3d at 744. We held that the weapon was a machinegun even though the gun’s original trigger activated each time a bullet was fired. That was so because
the gun had been modified such that it had a new trigEnglish, which contains more than 100,000 individual texts from the
1820s-2010s and more than 475 million words, shows zero usage of
the phrase “function of the trigger,” “function of a trigger,”
“function of triggers,” or “function of the triggers.” Corpus of
Historical American English, English Corpora, https://www.englishcorpora.org/coha/. Similarly, a search in the News on the Web
Corpus (NOW Corpus), which contains more than 16 billion words
from more than 27 million online texts from 2010 to present day,
shows only 24 uses of the phrase “function of the trigger”—all of
which are from news sources directly quoting a firearm statute;
there were zero uses of the phrase “function of a trigger,” “function
of triggers,” or “function of the triggers.” NOW Corpus, English
Corpora, https://www.english-corpora.org/now/.
The upshot is
that the phrase “by a single function of the trigger” is a novel phrase
created by Congress specifically to be used in these firearm statutes.
The Government stresses the existence of other ordinary phrases,
like “pull of the trigger.” Perhaps these ordinary phrases exist, but
Congress did not use them here.
27a
ger. As we held in United States v. Jokel, 969 F.2d 132,
135 (5th Cir. 1992), a trigger is just the “mechanism
. . . used to initiate the firing sequence.” The mechanism used to initiate the firing sequence in Camp was
the new switch. That switch operated by a single function, and so the firearm met the statutory definition of a
machinegun. Camp, 343 F.3d at 745.
Here, no party cites Camp for the proposition that
the legally relevant trigger is anything other than the
traditional trigger. And for good reason. All a nonmechanical bump stock does is allow the shooter to fire
at an increased rate by harnessing a weapon’s natural
recoil to re-engage the trigger, and by using the
shooter’s maintained forward force. The case might
well be different if we were considering a semiautomatic weapon equipped with a mechanical bump
stock. It could be the case that a switch activating a
mechanical bump stock would be the legal trigger. But
we are not considering that case. 8 Here, the definition
of “trigger” is not in dispute. If anything, Camp supports our conclusion because the trigger at issue in this
case is different in kind from the trigger at issue there.
The Government points to an unpublished Eleventh Circuit
case—which held that a mechanical bump stock called the Akins Accelerator is a machinegun for purposes of federal law—as support
for its argument that non-mechanical bump stocks operate by a single function of the trigger. See Akins v. United States, 312 F.
App’x 197, 200 (11th Cir. 2009). But that evidence cuts in the other
direction. Unlike non-mechanical bump stocks, a shooter using an
Akins Accelerator need only pull the trigger once to activate the firing sequence. The mechanical bump stock then maintained the
bump fire of its own accord. See 83 Fed. Reg. at 66517. Precisely
for that reason, our decision today would not apply to an Akins Accelerator.
8
28a
B
Even if a non-mechanical bump stock caused a semiautomatic rifle to operate by a single function of the trigger, the rifle would still need to operate automatically in
order to be a machinegun. 9 All generally agree that
here, automatically means “self-acting.” Oxford English Dictionary at 574 (1933) (“[s]elf-acting under conditions fixed for it, going of itself ”); see also Cargill, 20
F.4th at 1012; Guedes, 920 F.3d at 30; id. at 43 (Henderson, J. concurring in part and dissenting in part);
Aposhian, 958 F.3d at 986; Aposhian, 989 F.3d at 895
(Tymkovich, C.J., dissenting); Gun Owners of America,
19 F.4th at 905-06 (White, J., in support of affirmance);
id. at 912-13 (Murphy, J., in opposition to affirmance).
But the parties dispute whether the firing process enabled by a non-mechanical bump stock is self-acting.
It is not. As an initial matter, we must remember
that the phrase “by a single function of the trigger”
modifies the adverb “automatically.” Thus, the condition is satisfied only if it is the trigger that causes the
firearm to shoot automatically. See Guedes, 920 F.3d
at 43 (Henderson, J., concurring in part and dissenting
in part) (“ ‘Automatically’ cannot be read in isolation.
On the contrary, it is modified—that is, limited—by the
clause ‘by a single function of the trigger. ’ ”); Aposhian,
As explained above, because a semi-automatic firearm equipped
with a non-mechanical bump stock does not operate “by a single
function of the trigger,” such a weapon is not a machinegun, and we
must render judgment for Cargill. Our conclusions in Parts III.B
and V are each independent, alternative holdings. In the Fifth Circuit, “alternative holdings are binding precedent and not obiter dictum.” Jarkesy v. SEC, 34 F.4th 446, 459 n.9 (5th Cir. 2022) (quotation omitted).
9
29a
989 F.3d at 896 (Tymkovich, C.J., dissenting). That is
not how a bump stock works. Bump firing does not
maintain if all a shooter does is initially pull the trigger.
Rather, to continue the firing after the shooter pulls the
trigger, he or she must maintain manual, forward pressure on the barrel and manual, backward pressure on
the trigger ledge.
The Government argues that, taken together, those
actions create automatic fire. But Cargill would prevail even if that were true because those actions are not
“a single function of the trigger.” For example, the
ATF’s treatment of the Ithaca Model 37 “slam fire”
shotgun confirms that bump stocks do not enable automatic fire. With the Model 37, a shooter can pull the
trigger once and hold it. Then, after each pump with
the shooter’s non-trigger hand, a new shell is loaded and
immediately discharged. According to the ATF, the
Model 37 fires multiple shots by a single function of the
trigger, but it does not do so automatically because the
shooter must manually pump the shotgun with his nontrigger hand. See 83 Fed. Reg. at 66,534. By this
same logic, a rifle equipped with a non-mechanical bump
stock does not fire automatically because the shooter
must manually apply forward pressure on the barrel
with his or her non-trigger hand.
The Government recognizes this logic but argues
that it proves too much. After all, the Government
says, to operate a traditional automatic rifle, the shooter
must pull and hold the trigger to fire more than one
round. No one doubts that a traditional automatic
weapon is a machinegun for purposes of federal law.
And so it cannot be that a process is not automatic
30a
simply because it requires sustained input.
See
Guedes, 920 F.3d at 31; Aposhian, 958 F.3d at 987.
That argument makes the same mistake as before:
it untethers “single function of the trigger” from “automatically.” Restated, the statute requires that a machinegun be capable of firing automatically once the
trigger performs a single function.
An automatic
weapon satisfies this requirement because the act of
pulling and holding the trigger is one function, and that
function produces more than one shot. That force must
be maintained on the trigger does not change this conclusion. Stated succinctly:
[A] gun shoots automatically by a single function of
the trigger as long as the shooter need only manually
cause the trigger to engage in a “single” function in
order to fire multiple shots . . . So a typical machine gun qualifies even though the shooter pulls the
trigger and keeps it pressed down because that combined external influence still does no more than result in one action of the trigger.
Gun Owners of America, 19 F.4th at 915 (Murphy, J., in
opposition to affirmance); see also Guedes, 920 F.3d at
44 (Henderson, J., concurring in part and dissenting in
part) (“The statutory definition of machinegun does not
include a firearm that shoots more than one round automatically by a single pull of the trigger and then some
(that is, by constant forward pressure with the nontrigger hand).”) (internal quotation marks omitted and
emphasis omitted). As understood by the Navy-Marine Corps Court of Appeals:
It is incorrect to equate the holding of the trigger in
an automatic weapon with the holding of the trigger
31a
and the forward motion in a semi-automatic weapon
equipped with a bump stock. That is because the
former is shooting automatically by a single function
of the trigger, while the latter is relying on an additional human action beyond the mechanical self-acting and impersonal trigger function.
Alkazahg, 81 M.J. at 782-83.
We reiterate that a shooter can bump fire an ordinary
semi-automatic rifle even without a bump stock. But
nobody, not even the Government, contends that semiautomatic rifles are machineguns. That concession
damns the Government’s position. As Cargill recognizes, if ordinary bump firing constituted automatic fire,
the Final Rule would “convert a semiautomatic weapon
into a machinegun simply by how a marksman used the
weapon.” That absurd result reveals the flaw in the
Government’s line of reasoning.
In addition to implying absurd results, the Government’s position is quite telling. It would allow the use
of semi-automatic rifles, which can bump fire, but prohibit the use of non-mechanical bump stocks, even
though there is no mechanical difference between the
two forms of gunfire. Rather, the meaningful difference is that, with a non-mechanical bump stock, bump
firing is easier and can occur at a faster rate. That is a
distinction Congress certainly could have addressed in
the National Firearms Act and Gun Control Act. But
Congress did not prohibit machineguns according to
how quickly they fire. It prohibited machineguns according to the way that they fire. And semiautomatic
weapons do not fire “automatically,” even when
equipped with a non-mechanical bump stock.
32a
*
*
*
The definition of machinegun as set forth in the Gun
Control Act and National Firearms Act establishes two
conditions that must obtain in order for a weapon to
qualify. The weapon must operate “automatically” and
“by single function of the trigger.” According to the
statute’s unambiguous language, neither condition obtains as applied to a semi-automatic rifle equipped with
a non-mechanical bump stock. The failure of either
condition is sufficient to entitle Cargill to judgment.
IV
As introduced above, several of our sister circuits applied Chevron to challenges to this Final Rule, even
though no party requested its application. Because we
hold that the statute is unambiguous, Chevron deference
does not apply even if the Chevron framework does.
See Western Refining Southwest, 636 F.3d at 727. But
if the statute were ambiguous, Chevron would not apply
for any of the three reasons explained below.
A
First, Chevron does not apply for the simple reason
that the Government does not ask us to apply it. Indeed, the Government affirmatively argued in the district court that Chevron deference is unwarranted. As
other jurists have recognized in this context, that means
that the Chevron argument has been waived—not
merely forfeited. United States v. Olano, 507 U.S. 725,
733 (1993) (“Whereas forfeiture is the failure to make
the timely assertion of a right, waiver is ‘the intentional
relinquishment or abandonment of a known right.’ ”)
(quoting Johnson v. Zerbst, 304 U.S. 458, 464 (1938));
Guedes, 920 F.3d at 21 (“To the extent Chevron treat-
33a
ment can be waived, we assume that the government’s
posture in this litigation would amount to a waiver rather than only a forfeiture.”); Aposhian, 989 F.3d at 897
(“[W]hen a party chooses not to pursue a legal theory
potentially available to it, we generally take the view
that it is ‘inappropriate’ to pursue that theory in our
opinions.”) (internal citation and quotation marks omitted) (Tymkovich, C.J., dissenting).
That would seem to be the end of the inquiry, but we
recognize that one of our sister circuits has held that
Chevron cannot be waived. Guedes, 920 F.3d at 21-23;
see also Gun Owners of America, 19 F.4th at 899 n.5
(White, J., in support of affirmance). To be sure, we
have never held in a published case that Chevron must
be raised by the Government in order to apply. See
Albanil v. Coast 2 Coast, Inc., 444 F. App’x 788, 796 (5th
Cir. 2011). But the conclusion is obvious, and flows
from well-settled waiver principles. After all, that a
court should defer to the Government’s expressed interpretation is just a legal argument, and a party waives a
legal argument if it fails to raise the argument when presented with the opportunity.
See, e.g., Sindhi v.
Raina, 905 F.3d 327, 334 (5th Cir. 2018); Fruge v. Amerisure Mut. Ins. Co., 663 F.3d 743, 747 (5th Cir. 2011).
As explained in the Tenth Circuit’s consideration of
the Final Rule, “We refuse to consider arguments a
party fails to make because we ‘depend on the adversarial process to test the issues for our decision’ and are
concerned ‘ for the affected parties to whom we traditionally extend notice and an opportunity to be heard on
issues that affect them.’ ” Aposhian, 989 F.3d at 897
(Tymkovich, C.J., dissenting) (quoting Hydro Resources, Inc. v. EPA, 608 F.3d 1131, 1146 n.10 (10th Cir.
34a
2010) (en banc)); see also Carducci v. Regan, 714 F.2d
171, 177 (D.C. Cir. 1983) (Scalia, J.) (“The premise of our
adversarial system is that appellate courts do not sit as
self-directed boards of legal inquiry and research, but
essentially as arbiters of legal questions presented and
argued by the parties before them.”). We must not defer to the Government’s interpretation here for the simple reason that no party argues that we should.
If ordinary waiver principles were not enough, we
note also that it would contradict Chevron’s central justification to defer to the Government’s interpretation
without its urging us to do so. The justification is that
“ ‘policy choices’ should be left to executive branch officials ‘directly accountable to the people.’ ” Guedes, 140
S. Ct. at 790 (Gorsuch, J., statement respecting denial of
certiorari) (quoting Epic Systems v. Lewis, 138 S. Ct.
1612, 1630 (2018) and Chevron, 467 U.S. at 865)). Here,
the Government made a clear policy choice by declining
to seek Chevron deference. The very interest underlying Chevron demands that we respect the Government’s
choice and interpret the statute according to traditional
principles of statutory interpretation. See Aposhian,
989 F.3d at 898 (“If the agency disavows any reliance on
Chevron, who are we to second-guess it?”) (Tymkovich,
C.J., dissenting); Guedes, 140 S. Ct. at 790 (Gorsuch, J.,
statement respecting denial of certiorari) (“[C]ourts
must equally respect the Executive’s decision not to
make policy choices in the interpretation of Congress’s
handiwork.”).
Raising the issue sua sponte, the D.C. Circuit assumed that the Government’s actions were consistent
with waiver, but held that Chevron cannot be waived.
As an initial matter, that conclusion is likely inconsistent
35a
with Supreme Court precedent. Our highest Court
“has often declined to apply Chevron deference when
the government fails to invoke it.” Guedes, 140 S. Ct.
at 790 (Gorsuch, J., statement respecting denial of certiorari) (collecting cases); see, e.g., HollyFrontier Cheyenne Refining, LLC v. Renewable Fuels Ass’n, 141 S.
Ct. 2172, 2180 (2021) (“[T]he government is not invoking
Chevron. We therefore decline to consider whether
any deference might be due its regulation.”) (quotation
omitted).
The argument against waiver is based on the premise
that Chevron is a standard of review. Guedes, 920 F.3d
at 163; see also Gun Owners of America, 992 F.3d at 47778, vacated, 2 F.4th 576. It is certainly true that parties in litigation cannot waive the applicable standard of
review. E.g., United States v. Escobar, 866 F.3d 333,
339 n.13 (5th Cir. 2017) (quotation omitted). But Chevron is not a standard of review. The APA specifically
sets forth standards by which courts must review
agency actions—arbitrary and capricious, abuse of discretion, in excess of statutory authority, and so on. See
5 U.S.C. § 706. Chevron is merely a legal argument
that the Government can make to contend that its interpretation satisfies the relevant standard of review. 10
The Tenth Circuit has also held that a plaintiff ’s invocation of
Chevron—even if made for the purpose of disputing the Government’s interpretation of a statute, and absent argument from the
Government that Chevron should apply—is sufficient to require a
court to apply the framework. Aposhian, 958 F.3d at 981-82. We
respectfully disagree with that conclusion. Chevron’s purpose is to
recognize the institutional competence of executive agencies and to
defer to their expertise where appropriate. It would be inconsistent with that purpose to apply Chevron over the Government’s
objection just because a plaintiff preemptively addresses the frame10
36a
B
The Chevron framework does not apply for a second,
independent reason: the statute which the Final Rule
interprets imposes criminal penalties. As noted above,
the primary reason for Chevron is that it allows the executive branch to make policy decisions through the accrued expertise of administrative agencies. But in exchange, Chevron deference shifts the responsibility for
lawmaking from the Congress to the Executive, at least
in part. That tradeoff cannot be justified for criminal
statutes, in which the public’s entitlement to clarity in
the law is at its highest. See Guedes, 140 S. Ct. at 790
(Gorsuch, J., statement respecting denial of writ of certiorari) (“Before courts may send people to prison, we
owe them an independent determination that the law actually forbids their conduct.”); Esquivel-Quintana v.
Lynch, 810 F.3d 1019, 1027 (6th Cir. 2016) (Sutton, J.,
concurring in part and dissenting in part) (Applying
Chevron to criminal statutes would “permit the aggregation” of executive and legislative power “in the one
area where its division matters most: the removal of
citizens from society.”).
No precedent compels Chevron’s application here.
To the contrary, the Supreme Court has “never held
that the Government’s reading of a criminal statute is
entitled to any deference.” United States v. Apel, 571
work in an attempt to defend against the Government’s sponsored
interpretation. See Aposhian, 989 F.3d at 896 (Tymkovich, C.J.,
dissenting) (“This theory of waiver is untenable. Under the panel
majority’s theory, a party that challenges an agency’s interpretation
of a rule is forced to dance around Chevron, even where the government has not invoked it. Chevron becomes the Lord Voldemort of
administrative law, ‘the-case-which-must-not-be-named. ’ ”).
37a
U.S. 359, 369 (2014); see also Gutierrez-Brizuela v.
Lynch, 834 F.3d 1142, 1155 (10th Cir. 2016) (“The Supreme Court has expressly instructed us not to apply
Chevron deference when an agency seeks to interpret a
criminal statute.”) (Gorsuch, J., concurring). That is so
because “criminal laws are for the courts, not for the
Government, to construe.” Abramski v. United States,
573 U.S. 169, 191 (2014). For this reason, when “the
Government interprets a criminal statute too broadly
. . . or too narrowly . . . a court has an obligation
to correct its error.” Id. We must not apply Chevron
where, as here, the Government seeks to define the
scope of activities that subject the public to criminal
penalties. This is precisely the position we have taken
before, in an unpublished decision. United States v.
Garcia, 707 F. App’x 231, 234 (5th Cir. 2017) (“The Supreme Court has now resolved this uncertainty, instructing that no deference is owed to agency interpretations of criminal statutes.”).
Several of our sister circuits disagree, however. See
Guedes, 920 F.3d at 163-67; Aposhian, 958 F.3d at 98284. The disagreement stems from one paragraph in
the decision Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687 (1995). There,
the Supreme Court considered a Department of the Interior regulation that interpreted the Endangered Species Act’s criminal prohibition on “taking” an endangered species as including modification of the species’s
habitat. The Court did not conduct a Chevron analysis,
but upheld the regulation, concluding that it “owe[d]
some degree of deference [to] the [DOI’s] reasonable interpretation,” in part because of the “latitude the ESA
gives to [DOI] in enforcing the statute.” Id. at 703. It
also declined to apply the rule of lenity, reasoning that
38a
an administrative regulation does not necessarily invoke
the rule just because “the governing statute authorizes
criminal enforcement.” Id. at 704 n.18.
Several courts cite Babbitt for the proposition that
the Chevron framework applies with equal force to criminal regulations and displaces the rule of lenity, but it
does not support that conclusion. “While Babbitt certainly cited Chevron and used the word deference with
regard to the DOI’s interpretation, Babbitt did not discuss or decide whether Chevron applied nor did it analyze the challenge using Chevron, just as it did not decide whether the rule of lenity applied or analyze the
challenge using the rule of lenity.” Gun Owners of
America, 992 F.3d at 457, vacated, 2 F.4th 576. As explained by two members of the Supreme Court, Babbitt
did not purport to set forth a general rule respecting the
interpretation of criminal regulations: “The best that
one can say . . . is that in Babbitt[] [the Court] deferred, with scarcely any explanation, to an agency’s interpretation of a law that carried criminal penalties.
. . . Babbitt’s drive-by ruling, in short, deserves little
weight.” Whitman v. United States, 574 U.S. 1003, 135
S. Ct. 352, 353 (Scalia, J., joined by Thomas, J., respecting the denial of certiorari).
This is confirmed by subsequent Supreme Court
precedent, addressing the rule of lenity in relation to
Chevron and declining to defer to agency interpretations of criminal statutes. See Aposhian, 989 F.3d at
901 (Tymkovich, C.J., dissenting) (collecting cases).
Babbitt does not require us to apply Chevron in these
circumstances. Indeed, most proximate sources suggest otherwise. See Guedes, 140 S. Ct. at 790 (Gorsuch,
J., statement respecting denial of certiorari) (“[W]hat-
39a
ever else one thinks about Chevron, it has no role to play
when liberty is at stake.”). As such, Chevron does not
apply here because the statutory language at issue implicates criminal penalties.
C
Finally, we note a third reason why Chevron deference does not apply in these circumstances: that ATF
has adopted an interpretive position that is inconsistent
with its prior position. To apply Chevron here would
contravene one of the rule’s central purposes: “to promote fair notice to those subject to criminal laws.”
United States v. Kozminski, 487 U.S. 931, 952 (1988); see
also United States v. Kaluza, 780 F.3d 647, 669 (5th Cir.
2015) (“The rule ‘vindicates the fundamental principle
that no citizen should be held accountable for a violation
of a statute whose commands are uncertain, or subjected
to punishment that is not clearly prescribed.’ ”) (quoting
United States v. Santos, 553 U.S. 507, 514 (2008) (plurality op.)).11
If we were required to defer to the Government’s position, the Government could change the scope of criminal liability at any time. Indeed, that is exactly what it
has done here. Until 2017, the ATF had never classified non-mechanical bump stocks as machineguns. But
now the interpretation is reversed, and the Government
would criminalize behavior that it long recognized was
These fair-notice issues accentuate why Babbitt does not bar us
from applying the rule of lenity. In Babbitt, the Supreme Court expressly contemplated cases where it would be appropriate to apply
the rule of lenity. 515 U.S. at 704 n.18 (“Even if there exist regulations whose interpretations of statutory criminal penalties provide
such inadequate notice of potential liability as to offend the rule of
lenity, the [regulation at issue here] cannot be one of them.”).
11
40a
lawful. In considering one of the other cases involving
the regulation, one member of the Supreme Court explained the problem as such:
Chevron’s application in this case may be doubtful for
other reasons too. The agency used to tell everyone
that bump stocks don’t qualify as ‘machineguns.’
Now it says the opposite. The law hasn’t changed,
only an agency’s interpretation of it. How, in all
this, can ordinary citizens be expected to keep up?
. . . And why should courts, charged with the independent and neutral interpretation of the laws Congress has enacted, defer to such bureaucratic pirouetting?
Guedes, 140 S. Ct. at 790 (Gorsuch, J., statement respecting denial of certiorari); see also Aposhian, 989
F.3d at 900 (“When an agency plays pinball with a statute’s interpretation, as the ATF has here, fair notice
cannot be said to exist.”) (Tymkovich, C.J., dissenting);
Guedes, 920 F.3d at 181 (“The ATF’s interpretation of
‘machinegun’ gives anything but fair warning—instead,
it does a volte-face of its almost eleven years’ treatment
of a non-mechanical bump stock as not constituting a
‘machinegun.’ ”) (Henderson, J., concurring in part and
dissenting in part). 12
The concern respecting the consistency of agency
regulations is nothing new.
Indeed, the Supreme
Court has long recognized that an agency interpretation
that “conflicts with the agency’s earlier interpretation is
entitled to considerably less deference than a consistSee also Thomas Z. Horton, Lenity Before Kisor: Due Process,
Agency Deference, and the Interpretation of Ambiguous Penal Regulations, 54 Colum. J.L. & Soc. Probs. 629, 647-49 (2021).
12
41a
ently held agency view.” INS v. Cardoza-Fonseca, 480
U.S. 421, 446 n.30 (1987) (internal quotations omitted);
see also Cargill, 502 F. Supp. 3d at 1189 (quoting
Cardoza-Fonseza).
The concern is only magnified
where, as here, the Government’s interpretation of the
underlying statute carries implications for criminal liability. As such, Chevron does not apply because the
Government has construed the same statute in two, inconsistent ways at different points in time.
V
Turning to the rule of lenity, and assuming arguendo
that the relevant statute is ambiguous, we now consider
whether that “ambiguity concerning the ambit of criminal statutes should be resolved in favor of lenity.”
Rewis v. United States, 401 U.S. 808, 812 (1971) (citation
omitted). We conclude that the rule of lenity applies if
the statute is ambiguous.
We recognize that courts have considered two standards for whether a statute is sufficiently ambiguous to
trigger the rule of lenity. One standard asks whether
there is a “reasonable doubt” as to the statute’s meaning. See Reading Law at 299 (quoting Moskal v.
United States, 498 U.S. 103, 108 (1990)). The other inquires whether there is a “grievous ambiguity” in the
statute. See, e.g., Chapman v. United States, 500 U.S.
453, 463 (1991) (quoting Huddleston v. United States,
415 U.S. 814, 831 (1974)). The Supreme Court does not
appear to have decided which of these standards governs the rule of lenity. See Wooden v. United States,
142 S. Ct. 1063, 1075 (2022) (Kavanaugh, J., concurring)
(arguing in favor of the grievous-ambiguity standard);
id. at 142 S. Ct. at 1084 (Gorsuch, J., concurring in the
42a
judgment) (arguing in favor of the reasonable-doubt
standard).
But it does not matter which standard applies because the rule of lenity applies even under the more
stringent “grievously ambiguous” condition. One formulation of that standard provides that lenity applies if
a court cannot discern the statute’s meaning even “after
seizing everything from which aid can be derived.”
Wooden, 142 S. Ct. at 1075 (Kavanaugh, J., concurring)
(quoting Ocasio v. United States, 578 U.S. 282, 295 n.8
(2016)). Assuming that the statute at issue here is ambiguous, we can only “guess” at its definitive meaning.
Suchowolski, 838 F.3d at 534. We have availed ourselves of all traditional tools of statutory construction,
and in this circumstance, they fail to provide meaningful
guidance. That is sufficient to require application of
the rule of lenity irrespective of whether the reasonable
doubt or grievous ambiguity standard applies.
The dissenting opinion objects to our application of
lenity, arguing that we fail to explain why the statute at
issue here is grievously ambiguous. With this understanding, it concludes that our holding implies that “ambiguous statutes are always grievously ambiguous.”
Post at 57. This criticism misunderstands our holding.
We do not conclude that all ambiguous statutes are
grievously ambiguous—only that this one is.
Our conclusion fits comfortably into the dissenting
opinion’s own conceptualization of the grievous-ambiguity standard. At the very least, lenity is appropriate,
the dissenting opinion concedes, if after “having tried to
make sense of a statute using every other tool, we face
an unbreakable tie between different interpretations.”
Post at 56. That is the case here in two respects.
43a
First, the parties argue whether “a single function of the
trigger” refers to the firearm’s mechanics or to the
shooter’s pulling of the trigger. Second, the parties argue if the process of engaging the trigger and maintaining forward pressure on the gun’s forebody produces
“automatic” fire.
True, the precise meaning of “grievously ambiguous”
is not entirely clear. See Shular v. United States, 140
S. Ct. 779, 788 (2020) (Kavanaugh, J., concurring) (noting that “the Court has not always been perfectly consistent in its formulations [of grievous ambiguity]);
Reading Law at 299 (arguing that the term grievous ambiguity “provides little more than atmospherics, since it
leaves open the crucial question—almost invariably
present—of how much ambiguousness constitutes an
ambiguity”) (quoting United States v. Hansen, 772 F.2d
940, 948 (D.C. Cir. 1985)). But having utilized all available tools of statutory interpretation, and assuming arguendo that those two provisions are indeed ambiguous,
we are unable to resolve either of the ties. See Alkazahg, 81 M.J. at 784 (expressing “genuine confusion as
to what the statute means”). That is sufficient to conclude that this statute—and for purposes of this case,
only this statute—is grievously ambiguous.
The dissenting opinion also objects that applying lenity in this case wrongfully takes Congress’s prerogative
to establish federal crimes and transfers that power to
the Judiciary, violating the separation of powers. But
this is really just a repetition of the dissenting opinion’s
disagreement regarding the correct interpretation of
the statute at issue here. As we understand it, the
National Firearms Act and Gun Control Act do not
unambiguously criminalize the possession of a non-
44a
mechanical bump stock. To apply lenity in this case
preserves the separation of powers “by maintaining the
legislature as the creator of crimes.” Esquivel-Quintana, 810 F.3d at 1019. If ATF could change the scope
of criminal liability by issuing a regulation—free from
the taxing obligations of bicameralism and presentment
—the Executive could wield power that our Constitution
reserves to the Legislature.
The rule of lenity also prevents the possibility
whereby Congress passes an ambiguous criminal statute, only to be interpreted later by a federal agency.
See id. (“By applying lenity in this setting, last of all,
courts would avoid incentivizing Congress to enact hybrid statutes that duck under lenity’s imperatives, to say
nothing of other imperatives in construing criminal
laws.”). To be sure, it would be inconsistent with our
constitutional structure to apply lenity in an unprincipled manner to statutes that are not really ambiguous.
But here, we are wholly persuaded that if the definition
of “machinegun” does not unambiguously exclude nonmechanical bump stocks, its inclusion of the latter is at
the very least ambiguous. Given that conclusion, our
separation of powers is aided, rather than impeded, by
applying the rule of lenity.
The rule of lenity is a “time-honored interpretive
guideline.” Liparota v. United States, 471 U.S. 419,
429 (1985). We have applied it many times to construe
ambiguous statutes against imposing criminal liability.
See e.g., United States v. Cooper, 38 F.4th 428, 434 (5th
Cir. 2022); Kaluza, 780 F.3d at 669; United State v. Orellano, 405 F.3d 360, 370 (5th Cir. 2005). This case is no
different: assuming the definition of machinegun is
ambiguous, we are bound to apply the rule of lenity.
45a
That is, we are bound to construe the definition of machinegun to exclude a semi-automatic weapon equipped
with a non-mechanical bump stock. See Alkazahg, 81
M.J. at 784 (“We decline to step into the role of the legislature when the legislature has not been clear about
whether Appellant’s conduct was criminal.
Judge
Henry Friendly described the rule of lenity as ‘the
instinctive distaste against men languishing in prison
unless the lawmaker has clearly said they should.’
Here, we express that distaste.”) (quoting United States
v. Bass, 404 U.S. 336, 348 (1971)). Therefore, assuming
arguendo that the statute is ambiguous, we conclude
that the rule of lenity demands that we resolve that
ambiguity in favor of Cargill, and in turn conclude that
a non-mechanical bump stock is not a machinegun for
purposes of the National Firearms Act and Gun Control
Act.
VI
Cargill also argues that the passage of the Final Rule
is an exercise of legislative power, in violation of the
Constitution’s vesting all such power in Congress.
U.S. Const. art. I, § 1. Some have expressed serious
concern at the ATF’s lack of explicit authorization to interpret criminal statutes as such.
[W]e should feel deep discomfort at allowing an
agency to define the very criminal rules it will enforce
by implicit delegation. Such a delegation “turn[s]
the normal construction of criminal statutes upside
down, replacing the doctrine of lenity with a doctrine
of severity.” Carter v. Welles-Bowen Realty, Inc.,
736 F.3d 722, 730 (6th Cir. 2013) (Sutton, J., concurring). The delegation raises serious constitutional
46a
concerns by making ATF the expositor, executor,
and interpreter of criminal laws.
Aposhian, 989 F.3d at 900 (Tymkovich, C.J., dissenting).
We acknowledge this concern, especially in light of
statements made by several members the Supreme
Court calling into question the relevant standards for
legislative-power-delegation issues.
See Gundy v.
United States, 139 S. Ct. 2116, 2131-42 (2019) (Gorsuch,
J., dissenting, joined by Roberts, C.J., and Thomas, J.);
id. at 2130-31 (Alito, J., concurring in the judgment);
Paul v. United States, 140 S. Ct. 342 (2019) (Kavanaugh,
J., statement respecting the denial of certiorari).
We need not decide this question because multiple independent reasons compel us to hold the Final Rule to
be unlawful. But if more were needed, this issue may
well implicate the canon of constitutional avoidance.
Under that well-established doctrine, “where an otherwise acceptable construction of a statute would raise serious constitutional problems, the Court will construe
the statute to avoid such problems unless such construction is plainly contrary to the intent of Congress.”
Hersh v. United States, 553 F.3d 743, 754-55 (5th Cir.
2008) (quoting Edward J. DeBartolo Corp. v. Florida
Gulf Coast Building & Constr. Trades Council, 485 U.S.
568, 575 (1988)); see also Reading Law at 250.
For many jurists, the question of Congress’s delegating legislative power to the Executive in the context of
criminal statutes raises serious constitutional concerns.
See Guedes, 140 S. Ct. at 790 (Gorsuch, J., statement respecting denial of certiorari); Aposhian, 989 F.3d at 900
(Tymkovich, C.J., dissenting); Esquivel-Quintana, 810
F.3d at 1027 (Sutton, J., concurring in part and dissent-
47a
ing in part). We do not reach this issue because we do
not have to. But if we did, it would only provide more
support for the conclusion that a semi-automatic rifle
equipped with a non-mechanical bump stock is not a machinegun for purposes of federal law.
VII
Having determined that the judgment of the district
court must be reversed, we remand this case to the district court to enter judgment for Cargill and to determine the proper scope of relief. It is well-established
that “[a] plaintiff ’s remedy must be tailored to redress
the plaintiff ’s particular injury.” Gill v. Whitford, 138
S. Ct. 1916, 1934 (2018). And as an initial matter, vacatur of an agency action is the default rule in this Circuit.
See, e.g., Data Mktg. Partnership, LP v. United States
Dept. of Labor, 45 F.4th 846, 859 (5th Cir. 2022) (“The
default rule is that vacatur is the appropriate remedy.”);
see also Franciscan Alliance, Inc. v. Becerra, 47 F.4th
368, 374-75 (5th Cir. 2022) (“Vacatur is the only statutorily prescribed remedy for a successful APA challenge
to a regulation.”). But the parties have not briefed the
remedial-scope question, and it may be the case that a
more limited remedy is appropriate in these circumstances. We express no opinion on that question other
than to observe that the district court is well-placed to
answer the question in the first instance. We therefore
remand this case to the district court with the instruction that it enter judgment for Cargill and determine
what remedy—injunctive, declarative, or otherwise—is
appropriate to effectuate that judgment.
48a
VIII
Many commentators argue that non-mechanical
bump stocks contribute to firearm deaths and that the
Final Rule is good public policy. We express no opinion on those arguments because it is not our job to determine our nation’s public policy. That solemn responsibility lies with the Congress, and our task is confined to deciding cases and controversies, which requires us to apply the law as Congress has written it. 13
In defining the term machinegun, Congress referred
to the mechanism by which the gun’s trigger causes bullets to be fired. Policy judgments aside, we are bound
to apply that mechanical definition. And applying that
definition to a semi-automatic rifle equipped with a nonmechanical bump stock, we conclude that such a weapon
is not a machinegun for purposes of the Gun Control Act
and National Firearms Act. Chevron deference likely
has no role here either because the Government waived
it or because it does not apply to the Government’s interpretation of a statute imposing criminal penalties.
Finally, even if the statute were ambiguous—which it is
not—the rule of lenity would require that we interpret
the statute in Cargill’s favor.
As Justice Holmes
framed it years ago, “it is reasonable that a fair warning
The dissenting opinion accuses us of using the rule of lenity to
“legalize an instrument of mass murder.” Post at 61. But it is
Congress’s responsibility to unambiguously define the scope of criminal conduct. Congress having failed to do so, we deploy lenity to
retain the proper allocation of legislative power, not unsettle it.
And the dissenting opinion’s resort to policy argument only underscores the Judiciary’s proper role. It is our responsibility to apply
the law as written, regardless of what we think about the law’s wisdom or utility.
13
49a
should be given to the world in language that the common world will understand, of what the law intends to do
if a certain line is passed.” McBoyle, 283 U.S. at 27.
We cannot say that the National Firearms Act and Gun
Control Act give that fair warning that possession of a
non-mechanical bump stock is a crime.
The Final Rule promulgated by the ATF violates the
APA. We therefore REVERSE the judgment of the
district court and REMAND with instructions to enter
judgment for Cargill.
HAYNES , Circuit Judge, joined by RICHMAN, Chief
Judge, concurring in the judgment:
I concur in the judgment only because I reluctantly
conclude that the relevant statute is ambiguous such
that the rule of lenity favors the citizen in this case.
JAMES C. HO, Circuit Judge, joined by RICHMAN,
Chief Judge, and SOUTHWICK , Circuit Judge, concurring in part and concurring in the judgment:
Under the rule of lenity, “[p]enal statutes must be
construed strictly.” 1 WILLIAM BLACKSTONE, COMMENTARIES *88. “This is a rule of construction . . .
as old and well established as law itself.” United
States v. Wilson, 28 F. Cas. 699, 709 (C.C.E.D. Pa. 1830).
Our courts have thus long recognized that “all reasonable doubts concerning [the] meaning [of a penal
statute] . . . operate in favor of [the defendant].”
Harrison v. Vose, 50 U.S. 372, 378 (1850). We apply
the rule of lenity where “reasonable doubt persists
about a [criminal] statute’s intended scope.” Moskal v.
United States, 498 U.S. 103, 108 (1990). When standard principles of statutory interpretation “fail to establish that the Government’s position is unambiguously
50a
correct . . . [we] resolve the ambiguity in [the defendant’s] favor.” United States v. Granderson, 511
U.S. 39, 54 (1994).
The rule of lenity rests on “the principle that the
power of punishment is vested in the legislative, not in
the judicial department.” United States v. Wiltberger,
18 U.S. 76, 85 (1820) (Marshall, C.J.). The rule also ensures fair notice to citizens: “To make the warning
fair, . . . the line should be clear.” McBoyle v.
United States, 283 U.S. 25, 27 (1931) (Holmes, J.).
In sum, it is not enough to conclude that a criminal
statute should cover a particular act. The statute must
clearly and unambiguously cover the act.
Consider the disturbing problem of designer drugs.
The Controlled Substances Act of 1970 prohibits drugs
listed on certain schedules. See Thor v. United States,
554 F.2d 759, 762-63 (5th Cir. 1977). In response, a line
of synthetically produced drugs was created “to mimic
the pharmacological effects” of scheduled drugs, while
evading the Act. Clayton L. Smith, The Controlled
Substance Analogue Enforcement Act of 1986: The
Compromising of Criminalization, 16 Am. J. Crim. L.
107, 108 (1988).
Designer drugs differed in chemical composition
from scheduled drugs. But they were just as lethal.
So the same policy justifications for banning scheduled
drugs readily applied to designer drugs.
Yet all three branches agreed that existing law did
not ban designer drugs. See, e.g., Controlled Substance Analogs Enforcement Act of 1985: Hearing on
S. 1437 Before the S. Comm. on the Judiciary, 99th
Cong. 1st Sess. 2 (1985) (opening statement of Chairman
51a
Strom Thurmond) (“[U]nlawful activity under the Controlled Substances Act is defined with regard to the precise chemical makeup of the substances described by
schedules. . . . Make a minor alteration in the molecular structure of an outlawed drug . . . and you
have produced a . . . dangerous narcotic that is not
illegal.”); id. at 41-42 (statement of Stephen S. Trott, Assistant Attorney General, Criminal Division, Department of Justice) (“[I]f a particular substance is not included in one of the schedules, it is not unlawful to manufacture or to distribute it . . . despite the potential
for abuse. . . . ”); United States v. Gavrilovic, 551
F.2d 1099, 1106 (8th Cir. 1977) (reversing a conviction
where a concededly dangerous narcotic had not been
properly added to a schedule).
So a new act of Congress was required to get at the
problem of designer drugs. And that’s why Congress
enacted the Controlled Substance Analogue Enforcement Act of 1986. Pub. L. No. 99-570, §§ 1201-04, 100
Stat. 3207, 3207-13 to 3207-14 (1986). See also United
States v. Muhammad, 14 F.4th 352, 355 (5th Cir. 2021)
(“[T]he Analogue Act is an antidote to statutory evasion:
It expands the CSA’s coverage to include substances
that, while technically not on the schedules, mimic those
that are.”).
Bump stocks present the same basic conundrum as
designer drugs. Federal law criminalizes the possession of fully automatic machineguns. See 18 U.S.C.
§ 922(o)(1) (machinegun ban); 26 U.S.C. § 5845(b) (machinegun definition). That prohibition does not apply
to semiautomatic weapons. See Gun Control Act of
1968, § 201, 82 Stat. 1231 (codified at 26 U.S.C. § 5845(b))
52a
(amending the 1934 federal definition of “machinegun”
to omit weapons that shoot “semiautomatically”).
But bump stocks now allow semiautomatic weapons
to mimic automatic machineguns.
By attaching a
bump stock to a semiautomatic firearm, the shooter can
simulate the experience of firing an automatic machinegun. See 83 Fed. Reg. 66,515-16.
Just as designer drugs achieve the same lethality as
scheduled drugs, bump stocks allow semiautomatic
weapons to achieve the same lethality as fully automatic
machineguns. But once again, Congress must take action if it wishes to criminalize bump stocks, just as it did
during the 1980s when it came to designer drugs.
That’s because federal law defines “machinegun” as
a weapon that shoots more than one shot “automatically
. . . by a single function of the trigger.” 26 U.S.C. §
5845(b). There are competing theories as to whether
this language is best construed to cover bump stocks.
In my own view, the relevant language is at best ambiguous. That makes this an easy case for invoking the
rule of lenity. Accordingly, I agree that we should reverse.
I.
Federal law defines a machinegun as a “weapon
which shoots . . . automatically more than one shot
. . . by a single function of the trigger.” 26 U.S.C.
§ 5845(b). The definition also includes “any part designed and intended . . . for use in converting a
weapon into a machinegun.” Id. Violators of the machinegun ban risk up to ten years in federal prison. 18
U.S.C. § 924(a)(2).
53a
I see at least two challenges with reading § 5845(b) to
cover bump stocks. To begin with, it’s at best ambiguous whether a semiautomatic weapon equipped with a
bump stock is indeed capable of shooting more than one
shot by “a single function of the trigger.” Id. And
even if I could get past that problem, it’s also ambiguous
at best whether the weapon does so “automatically.”
Id. So the rule of lenity requires us to reverse.
A.
The phrase “single function of the trigger” is not a
matter of common parlance. No one has identified an
example of this phrase ever being used in any context
other than this statute.
So it’s a term that requires interpretation. And in
this context, the interpretive steps it takes to get from
“single function of the trigger” to the criminalization of
bump stocks fall short of the fair notice that lenity requires.
What does “single function of the trigger” mean?
“[F]unction” means “action.” WEBSTER’S NEW INTERNATIONAL DICTIONARY 1019 (2nd ed. 1934). But where
does that leave us?
If it means that there is a single action on the trigger
from the shooter’s perspective, then this language might
very well apply to bump stocks. That’s because a single action on the trigger by the shooter is enough to
spray multiple bullets.
But if the phrase means that there is a single action
by the trigger from the weapon’s perspective, then this
language would not apply to bump stocks. That’s because from the weapon’s perspective, a single action by
the trigger releases just one bullet. See, e.g., Gun
54a
Owners of Am., Inc. v. Garland, 992 F.3d 446, 469 (6th
Cir. 2021) (“the question is whether ‘function’ is referring to the mechanical process (i.e., the act of the trigger’s being depressed, released, and reset) or the human
process (i.e., the shooter’s pulling, or otherwise acting
upon, the trigger)”), vacated on reh’g en banc, 2 F.4th
576 (6th Cir. 2021).
I conclude that grammar and syntax are at best inconclusive, and that lenity therefore requires us to side
with the citizen over the government.
The problem here is the distinction between what
classical grammarians call the “subjective genitive” and
the “objective genitive.” See, e.g., LAUREL J. BRINTON, THE STRUCTURE OF MODERN ENGLISH: A LINGUISTIC INTRODUCTION 108 (2000) (“The phrase the
shooting of the hunters is ambiguous between subjective
and objective genitive readings because it can mean either ‘the hunters shoot X’ or ‘X shoots the hunters.’ ”);
see also THOMAS KERCHEVER ARNOLD, AN ENGLISH
GRAMMAR FOR CLASSICAL SCHOOLS 98 (1848); SIDNEY
GREENBAUM & RANDOLPH QUIRK, A STUDENT’S GRAMMAR OF THE ENGLISH LANGUAGE 103 (1990).
Take, for example, the phrase “the love of my children.” That phrase could mean that my children love
me (in other words, my children are the subject of love).
Or it could mean that I love my children (so my children
are the object of love).
Only context can clarify whether children are the
subject or the object of love. Compare EMMA D.E.N.
SOUTHWORTH, VICTOR’S TRIUMPH 97 (1874) (“[S]he
could not win the love of children.”) (subjective genitive), with Henry James, Stephen Dewhurst’s Autobiog-
55a
raphy 54 THE ATLANTIC MONTHLY 649, 650 (1884)
(“[S]he had a most vivacious love of children.”) (objective genitive).
Consider another example: “the fear of the soldiers.” Without clarifying context, this could mean
that the soldiers are fearful (the soldiers are the subject
of fear). Or it could mean that someone else is fearful
of the soldiers (the soldiers are the object of fear).
Compare Jan Palmper Fear: Soldiers and Emotion in
Early Twentieth-Century Russian Military Psychology, 68 SLAVIC REV. 259, 270 n.38 (2009) (“[T]he fear
that officers inspired in soldiers could also cause harm[].
. . . Only just, law-abiding behavior on the part of officers could keep this particular fear of soldiers in
check.”) (subjective genitive), with C. Stanley Smith,
Five Days, 1927 THE ATLANTIC MONTHLY 836, 841
(“The fact that I also felt absolutely no fear of the soldiers contributed largely to my safety.”) (objective genitive).
Naturally, then, this same ambiguity can also exist
when a genitive construction modifies the term “function.”
For example, the phrase “function of the polls” could
refer to what polls do (polls are the subject). See A.
Stuart, Norman L. Webb & D. Butler, Public Opinion
Polls, 142 J. ROYAL STAT. SOC’Y 443, 447 (1979) (“The
second and most obvious function of polls is that they
show the progress of electoral campaigns in a purely informative sense.”) (subjective genitive).
Or it could refer to what voters do at the polls (polls
are the object). See H.W. Warner, The Republic:
Things as They Are at Present, Compared with the
56a
Past, 4 AM. REV. 278, 279 (1849) (early American lawmakers established age, residency, and property requirements as “necessary qualifications for the function
of the polls”) (objective genitive).
By the same token, a “function of the trigger” could
mean what the trigger does (the trigger is the subject).
Or it could mean what the shooter does to the trigger
(the trigger is the object). A “single function of the
trigger” could mean that the trigger acts once—or that
the shooter acts once on the trigger.
The government’s reading prevails if it’s clear that
the trigger is the object, and the shooter is the implied
subject. But there’s nothing inherent about the phrase
“function of the trigger” that tells us that the trigger is
the object rather than the subject.
So grammar alone can’t dictate whether we should
read the statute from the machine’s perspective (subjective genitive) or the shooter’s perspective (objective
genitive). As the D.C. Circuit explained: “[T]he text
is silent on the crucial question of which perspective is
relevant. A mechanical perspective . . . might focus on the trigger’s release of the hammer, which causes
the release of a round. From that perspective, a ‘single
function of the trigger’ yields a single round of fire when
a bump-stock device moves the trigger back and forth.
By contrast, from the perspective of the shooter’s action, the function of pulling the trigger a single time results in repeated shots when a bump-stock device is engaged. From that perspective, then, a ‘single function
of the trigger’ yields multiple rounds of fire.” Guedes
v. Bureau of Alcohol, Tobacco, Firearms & Explosives,
920 F.3d 1, 29 (D.C. Cir. 2019).
57a
In the examples provided above, the history or context of a particular phrase sheds light on whether it contains a subjective or objective genitive. Take another
example: “The fear of the Lord is the beginning of wisdom.” PSALM 111:10. Construed as a subjective genitive, “the fear of the lord” could refer to an anxious aristocrat, afraid of an overweening monarch or unruly populace. But we know that the Bible means something
very different—that the wise man fears God.
Unlike “fear of the Lord,” a “single function of the
trigger” does not offer much by way of history or context. No example of its usage in any other context has
been provided by anyone in this litigation. Congress
appears to have coined the phrase just for this statute. 1
The plurality claims that its interpretation is supported by context: A neighboring provision, § 5845(c), refers to a “single pull of
the trigger”—whereas § 5845(b) uses the phrase “single function of
the trigger.” See ante, at 20-21. So the plurality infers that the
term “pull” must be distinct from the term “function”—if “pull” signifies the shooter’s perspective, then “function” must signify the
weapon’s perspective. Cf. Gun Owners, 992 F.3d at 469 (“pull” suggests “shooter’s” perspective); Guedes, 920 F.3d at 29 (same).
But the dissent would presumably counter with legislative history suggesting that the terms are interchangeable rather than distinct. See Cargill v. Garland, 20 F.4th 1004, 1010 (5th Cir. 2021),
reh’g granted, 37 F.4th 1091 (5th Cir. 2022) (quoting House report
statement that the statute defines machinegun as “a weapon designed to shoot more than one shot without reloading and by a single
pull of the trigger”); id. (statement of Karl T. Frederick, President,
National Rifle Association of America) (equating “single pull of the
trigger” with “single function of the trigger”). And whatever one
may think of legislative history, the Supreme Court has repeatedly
looked to it before invoking lenity. See, e.g., Moskal, 498 U.S. at
108; Granderson, 511 U.S. at 54.
1
58a
As between construing “single function of the trigger” from the weapon’s perspective or the shooter’s perspective, then, the statute appears to be in equipoise.
And statutory equipoise is a textbook case for lenity. 2
So there’s some evidence that the terms are distinct, and some
that the terms are interchangeable. The evidence thus appears to
be in equipoise—a classic case for lenity.
2
Both the plurality and the dissent resist the notion of equipoise.
They both point to other words in § 5845(b) that arguably favor their
respective positions: The plurality invokes the subject of the sentence (“machinegun”)—while the dissent relies on a prepositional
phrase (“without manual reloading”).
Neither inference seems warranted. Neither the plurality nor
the dissent cites a rule of grammar that says that a subject or prepositional phrase tells us whether to read a subsequent phrase as a
subjective or objective genitive. And I’m aware of none.
For example, the plurality notes that, under § 5845(b), “machinegun means . . . any weapon which shoots . . . automatically more than one shot . . . by a single function of the trigger.”
26 U.S.C. § 5845(b). So “[t]he subject of the sentence . . . is
machinegun.” Ante, at 19. Therefore, the plurality argues, it
must be the perspective of the machinegun, not the shooter, that
dictates how we read “function of the trigger.”
But no rule of grammar supports this inference. Suppose I offer this definition: “Sugar means a sweet carbohydrate that enhances the enjoyment of food.” Naturally, we would read “enjoyment of food” from the perspective of the eater, not the food—even
though sugar is the subject of the sentence, and the sentence never
mentions the eater.
The dissent commits a similar error. It claims that § 5845(b)
must be read from the shooter’s perspective because it defines “machinegun” to mean a weapon that fires multiple shots, “without manual reloading,” by a single function of the trigger. 26 U.S.C.
§ 5845(b). The phrase “without manual reloading” means that no
reloading is performed by the shooter. So the dissent theorizes
that “single function of the trigger” must likewise refer to an action
performed by the shooter. See post, at 57 n.5.
59a
B.
There’s another ambiguity in the statute. Does a
semiautomatic weapon equipped with a bump stock
shoot multiple bullets “automatically?” Each side puts
forth its competing theory with great force. But neither deals a fatal blow to the other—which is why, once
again, lenity compels reversal.
Cargill argues that a bump stock doesn’t shoot multiple bullets “automatically” because it requires “constant forward pressure with the non-trigger hand.”
Guedes, 920 F.3d at 44 (Henderson, J., concurring in
part and dissenting in part). “Automatic” means “selfacting.” OXFORD ENGLISH DICTIONARY at 574 (1933).
So Cargill argues that the need for human input means
that bump stocks do not shoot automatically, because
they do not shoot in a self-acting fashion.
But the government counters that the term “automatic” need not necessarily mean no human input. It
could just mean less human input. And that would
make it ambiguous at best whether “automatic” includes
or excludes bump stocks.
Consider an automatic sewing machine. With a machine that sews automatically, you don’t just push a
button—you also move the cloth forward with your
hand.
But once again, no rule of grammar supports such an inference.
Suppose I offer this definition: “A well-trained army means an
army that follows orders, without constant reminding, due to the
fear of the soldiers.” Naturally, “without constant reminding”
means no reminding is done by officers, not soldiers. Yet the
phrase “fear of the soldiers” obviously refers to a feeling felt by soldiers. The soldiers are afraid—not the officers.
60a
This is similar to a bump stock. You don’t just pull
the trigger with your finger—you also apply pressure
with your non-trigger hand. See Guedes, 920 F.3d at
30.
Likewise, with an automatic car—one that shifts
gears automatically—you still have to “maintain[]
enough constan
This text is long and has been trimmed here. Open the source document for the complete record.
This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.