Amicus Curiae Brief — Smith & Wesson Brands, Inc., et al., Petitioners v. Estados Unidos Mexicanos

No. 23-1141

IN THE

Supreme Court of the United States

_________

SMITH & WESSON BRANDS, INC., et al.,

Petitioners,

V.

ESTADOS UNIDOS MEXICANOS,

Respondent.

_________

On Writ of Certiorari to the United States

Court of Appeals for the First Circuit

_________

AMICUS BRIEF OF DEAN ERWIN

CHEMERINSKY AND PROFESSOR

CHRISTOPHER KUTZ IN SUPPORT OF

RESPONDENT

_________

JAMES D. GOTZ

HAUSFELD LLP

One Marina Park Drive

Suite 1410

Boston, MA 02210

(617) 207-0600

jgotz@hausfeld.com

ROBERT S. PECK

Counsel of Record

CENTER FOR CONSTITUTIONAL

LITIGATION, PC

1901 Connecticut Avenue, NW

Suite 1101

Washington, DC 20009

(202) 944-2874

robert.peck@cclfirm.com

Counsel for Respondent

ii

TABLE OF CONTENTS

INTEREST OF AMICI CURIAE ............................... 1

INTRODUCTION AND SUMMARY OF

ARGUMENT ......................................................... 2

ARGUMENT .............................................................. 6

I. SMITH & WESSON DOES NOT AND

CANNOT JUSTIFY ITS ONE-SIZEFITS-ALL APPROACH TO PLCAA’S

LIMITED-PURPOSE USE OF

PROXIMATE CAUSE. .......................................... 6

A. Proximate Cause is a Statute-Specific

Concept............................................................. 7

B. PLCAA

Has

No

Independent

Proximate Cause Standard, But

Instead Incorporates the Standard

Imposed by the Statute Violated................... 12

II. EVEN IF A DIRECTNESS STANDARD

WERE APPLIED AND DISPLACED

FORESEEABILITY, IT WOULD

PROVIDE NO BASIS FOR DISMISSAL

UNDER PLCAA. ................................................. 19

A. Even the Directness Test Involves

Flexibility and Consideration of the

Relevant Circumstances. ............................... 21

B. A Causal Chain Can Always Be

Creatively Extended, But that Does

Not Per Se Deny Liability. ............................ 21

iii

TABLE OF CONTENTS—Continued

III.THE ORDINARY COURSE OF

BUSINESS SUPPLIES NO DEFENSE

TO AIDING-AND-ABETTING

LIABILITY. ......................................................... 23

A. Aiding and Abetting Liability Was

Developed to Address Misconduct Like

that Alleged Here. ......................................... 25

B. Mexico’s

Allegations

Fit

the

Requirements for Aiding and Abetting

Liability. ......................................................... 31

CONCLUSION ......................................................... 33

iv

TABLE OF AUTHORITIES

Cases

Anza v. Ideal Basic Steel Supply Corp., 547

U.S. 451 (2006) ........................................................ 6

Aspinall v. Philip Morris Cos., Inc., 813

N.E.2d 476 (Mass. 2004) ....................................... 17

Bank of Am. Corp. v. City of Miami, 581

U.S. 189 (2017) ........................................................ 4

Bartenwerfer v. Buckley, 598 U.S. 69

(2023) ..................................................................... 24

Blue Shield of Va. v. McCready, 457 U.S.

465 (1982)............................................................... 23

Bridge v. Phoenix Bond & Indem. Co., 553

U.S. 639 (2008) ........................................................ 7

Camp v. Dema, 948 F.2d 455 (8th Cir.

1991)....................................................................... 24

Cent. Bank of Denver, N.A. v. First

Interstate Bank of Denver, N.A., 511 U.S.

164 (1994)............................................................... 25

City of Miami v. Wells Fargo & Co., 923

F.3d 1260 (11th Cir. 2019), cert. granted,

judgment vacated sub nom. Wells Fargo

& Co. v. City of Miami, 140 S. Ct. 1259

(2020) ..................................................................... 21

Clapper v. Amnesty Int’l USA, 568 U.S. 398

(2013) ..................................................................... 15

Cobb v. Indian Springs, Inc., 522 S.W.2d

383 (Ark. 1975) ...................................................... 31

CSX Transp., Inc. v. McBride, 564 U.S. 685

(2011) ........................................................... 2, 12, 13

v

TABLE OF AUTHORITIES—Continued

Direct Sales Co. v. United States, 319 U.S.

703 (1943)...................................................... 6, 29-31

Derosier v. New England Tel. & Tel. Co.,

130 A. 145, 152 (N.H. 1925) .................................. 10

Doull v. Foster, 163 N.E.3d 976 (2021) .................... 18

Exxon Co., U.S.A. v. Sofec, Inc., 517 U.S.

830 (1996)............................................................... 10

Flood v. Southland Corp., 616 N.E.2d 1068

(Mass. 1993) ........................................................... 17

Halberstam v. Welch, 705 F.2d 472 (D.C.

Cir. 1983) ................................................ 5, 26, 28-30

Hemi Group, LLC v. City of New York, 559

U.S. 1 (2010) .......................................................... 21

Holmes v. Sec. Inv. Prot. Corp., 503 U.S.

258 (1992).............................. 2, 4, 7, 8, 10-12, 16, 20

Hyannis Anglers Club, Inc. v. Harris

Warren Com. Kitchens, LLC, 78 N.E.3d

784 (2017)............................................................... 19

Ileto v. Glock Inc., 349 F.3d 1191, 1194 (9th

Cir. 2003), cert. denied sub. nom., China

N. Indus. Corp. v. Ileto, 543 U.S. 1050

(2005) ..................................................................... 13

Ileto v. Glock, Inc., 565 F.3d 1126 (9th Cir.

2009), cert. denied, 560 U.S. 924 (2010) ......... 13, 14

Jerome B. Grubart, Inc. v. Great Lakes

Dredge & Dock Co., 513 U.S. 527 (1995) .............. 10

Keel v. Hainline, 331 P.2d 397 (Okla.

1958) ................................................................. 28,29

Khulumani v. Barclay Nat’l Bank Ltd., 504

F.3d 254 (2d Cir. 2007) .......................................... 25

vi

TABLE OF AUTHORITIES—Continued

Lexmark Int’l, Inc. v. Static Control

Components, Inc., 572 U.S. 118 (2014) .... 2, 4, 7, 10,

........................................................ 11, 12, 15, 22, 23

Nye & Nissen v. United States, 336 U.S. 613

(1949) ..................................................................... 25

Paroline v. U.S., 572 U.S. 434 (2014) ...................... 10

Rosemond v. United States, 572 U.S. 65

(2014) ..................................................................... 30

Russell v. Marboro Books, 183 N.Y.S.2d 8

(N.Y. Sup. Ct. 1959) ..................................... 5, 26, 27

Smith & Wesson Corp. v. City of Gary, 875

N.E.2d 422 (Ind. Ct. App. 2007), trans.

denied (2009)............................................................ 8

Sosa v. Alvarez-Machain, 542 U.S. 692

(2004) ....................................................................... 9

Soto v. Bushmaster Firearms Int’l, LLC,

202 A.3d 262, cert. denied sub. nom.

Remington Arms Co., LLC, v. Soto, 140 S.

Ct. 513 (2019)......................................................... 16

Students for Fair Admissions, Inc. v.

President & Fellows of Harvard Coll., 600

U.S. 181 (2023) ........................................................ 8

Twitter, Inc. v. Taamneh, 598 U.S. 471

(2023) ..................................................... 5, 24, 26, 30

United States v. Peoni, 100 F.2d 401 (2d

Cir. 1938) ............................................................... 25

Warth v. Seldin, 422 U.S. 490 (1975) ...................... 10

Whittaker v. Saraceno, 635 N.E.2d 1185

(Mass. 1994) ..................................................... 17, 18

vii

TABLE OF AUTHORITIES—Continued

Statutes

18 U.S.C. § 2 ............................................................. 25

Federal Employers’ Liability Act, 45 U.S.C.

§ 51 et seq. .............................................................. 12

Massachusetts Consumer Protection Act,

Mass. Gen. Laws c. 93A ........................................ 17

Protection of Lawful Commerce in Arms

Act (PLCAA), Pub. L. No. 109-92, 109

Stat. 2005, 15 U.S.C.A. §§ 7901 to 7903 .... 1, 3, 5, 6,

................................................................. 8, 12-19, 23

Other Authorities

1 T. Schoenbaum, Admiralty and Maritime

Law (2d ed. 1994) .................................................. 10

4 F. Harper, F. James, Jr., & O. Gray, Torts

(2d ed. 1986) ........................................................... 18

Dan B. Dobbs et al., The Law of Torts (2d.

ed. 2024) ................................................................. 18

David W. Robertson, The Common Sense of

Cause in Fact, 75 Tex. L. Rev. 1765

(1997) ....................................................................... 9

Hillel Y. Levin & Timothy D. Lytton, The

Contours of Gun Industry Immunity:

Separation of Powers, Federalism, and

the Second Amendment, 75 Fla. L. Rev.

833 (2023)............................................................... 13

Jill E. Fisch, Cause for Concern: Causation

and Federal Securities Fraud, 94 Iowa L.

Rev. 811 (2009) ........................................................ 9

Restatement (Second) of Torts (1965) ....................... 9

viii

TABLE OF AUTHORITIES—Continued

Restatement (Third) of Torts: Liab. for

Physical & Emotional Harm (2010) .............. 7, 9, 18

Sandra

F.

Sperino,

Discrimination

Statutes, the Common Law, and

Proximate Cause, 2013 U. Ill. L. Rev. 1

(2013) ..................................................................... 12

W. Keeton, D. Dobbs, R. Keeton, & D.

Owen, Prosser and Keeton on Law of

Torts (5th ed. 1984) ....................................... 7, 9, 12

INTEREST OF AMICI CURIAE1

Amici curiae are distinguished law professors

whose scholarship covers constitutional law, federal

jurisdiction, criminal law and procedure, and

international law. As scholars on issues raised by the

Questions Presented, they offer their views on the

function of proximate cause and aiding and abetting

with respect to the Protection of Lawful Commerce in

Arms Act (PLCAA).

Amici are listed below with titles and institutional

affiliations included for identification only:

Erwin Chemerinsky is the Dean and Jesse H.

Choper Distinguished Professor of Law at the

University of California, Berkeley School of Law. He

is author of nineteen books, including leading

casebooks and treatises about constitutional law,

criminal procedure, and federal jurisdiction; and,

Christopher Kutz is the C. William Maxeiner

Distinguished Professor of Law at the University of

California, Berkeley School of Law. His work focuses

on moral, political and legal philosophy, and he has

particular interest in the foundations of criminal,

international, and constitutional law. His relevant

relevant scholarship explores shared criminal

1

Pursuant to Rule 37.6, counsel for amici affirms this brief was

not authored in whole or in part by counsel for any party and

that no person or entity, other than amici curiae or their counsel

made a monetary contribution to the preparation or submission

of the brief.

2

responsibility, including his book, Complicity: Ethics

and Law for a Collective Age.

INTRODUCTION

ARGUMENT

AND

SUMMARY

OF

Smith & Wesson’s one-size-fits-all purported

federal proximate-cause standard has no basis in this

Court’s precedents and ignores the type of inquiry

that caselaw mandates. This Court has instructed

that the proper proximate cause approach examines a

statute’s text and legislative history. Holmes v. Sec.

Inv. Prot. Corp., 503 U.S. 258, 267 (1992).

Federal laws utilize a variety of proximate-cause

standards, rather than a single uniform one, that

depends on the nature of the statutory cause of action.

Lexmark Int’l, Inc. v. Static Control Components, Inc.,

572 U.S. 118, 133 (2014). As a result, proximate cause

is statute specific. For example, the Federal

Employers Liability Act applies on a “relaxed

standard,” CSX Transp., Inc. v. McBride, 564 U.S.

685, 692 (2011), while antitrust actions use the

standard that Smith & Wesson wrongly assert is the

only federal standard. See Holmes, 503 U.S. at 269

(describing a direct-relationship test as “one of the

central elements” of Clayton Act causation). Even

RICO, modeled after the antitrust laws, utilizes

varying proximate-cause standards depending on the

predicate act that triggers its availability. Id. at 288

(Scalia, J., concurring). Smith & Wesson makes no

attempt to understand these critical differences.

Proximate cause serves an extremely limited role,

if any, in the first Question Presented to this Court

because the 2005 Protection of Lawful Commerce in

3

Arms Act (PLCAA), Pub. L. No. 109-92, 109 Stat.

2005, 15 U.S.C.A. §§ 7901 to 7903, creates no cause of

action. Instead, the statute conveys immunity against

certain causes of action but then retracts that

immunity when plaintiffs plead a State or federal

statutory violation. PLCAA uses the term “proximate

cause” to examine whether the statutory violation

validly applies, but, in this usage, it imposes no

federal standard of its own. Instead, because it

depends on a predicate statutory violation for its

immunity exception that is applicable to certain

actions, it necessarily incorporates the proximatecause standard applicable of the other statute.

Whether that standard is a State or federal standard,

then, depends on the statute allegedly violated.

For PLCAA’s purposes, a reviewing court must

determine whether a statutory violation supports the

exception to PLCAA immunity. Smith & Wesson

completely fails to examine the relevant proximate

cause standard for any statutory violation. Its

assertion that proximate cause is unmet without

further exploration of the underlying predicate

exception-triggering statute, then, is merely

conclusory.

This interpretation does not ignore the

congressional choice in using the words “proximate

cause’ in the statute, which must be respected.

However, given its limited purpose in a statute that

creates no cause of action, we submit that the direct,

one-step approach this Court has adopted for certain

other federally created causes of action is

inappropriate. Here, where Congress chose to step

aside and allow what it deemed a legitimately

4

developed cause of action to go forward, it does not

seek to overlay a federalized proximate cause of action

on a State, or displace the applicable proximate-cause

standard of a different federal statute.

Even if one were to apply the direct-relation test

that Smith & Wesson advocates, Mexico’s pleading

satisfies the test. Mexico has alleged a substantial,

non-derivative injury that is not just reasonably

foreseeable, but also is necessarily and directly

connected to the gun manufacturers’ conduct in

marketing and selling its products with an eye to the

Mexican market, and thus plausibly bears “some

direct relation between the injury asserted and the

injurious conduct alleged.” Holmes, 503 U.S. at 268.

Nothing more is necessary, even under that standard.

Equally unavailing is Smith & Wesson’s claim that

a literal first step guides the analysis. This Court has

explained that “[w]hat falls within that ‘first step’

depends in part on the ‘nature of the statutory cause

of action,’” and an assessment “‘of what is

administratively possible and convenient.’” Bank of

Am. Corp. v. City of Miami, 581 U.S. 189, 203 (2017).

One can always atomize the causal chain to make it

appear overextended, but type of creativity does not

guide this Court’s analysis. Instead, as in Lexmark,

which involved a derivative injury not present here,

this Court acknowledged the multi-step nature of the

causal chain while still finding proximate cause met

because the facts pleaded showed no discontinuity

and a 1:1 relationship from the act and the injury. 572

U.S. at 139.

5

Proximate cause, then, erects no obstacle to this

action and, indeed, PLCAA contemplates the

involvement of third parties in the causal chain.

Smith & Wesson’s assertion that its conduct of

“business as usual” immunizes it from aiding-andabetting liability is equally unavailing. “Business as

usual” hardly forecloses liability. Rather, it can serve

as the basis for liability when the business activities

knowingly exploit opportunities that to supply, in this

instance, guns, to a criminal market, as Mexico has

alleged. Still, Mexico’s complaint alleges facts that

indicate that Smith & Wesson had the type of

knowledge of and involvement in defendant gun

sellers’ misconduct that goes beyond mere “business

as usual.”

This Court has accurately recognized that

Halberstam v. Welch, 705 F.2d 472 (D.C. Cir. 1983),

provides significant guidance in applying aiding and

abetting in the civil context because that court

undertook an extensive survey of secondary liability

in tort. See Twitter, Inc. v. Taamneh, 598 U.S. 471,

484 (2023). One of the cases that Halberstam,

reviewed with approval, Russell v. Marboro Books,

183 N.Y.S.2d 8 (N.Y. Sup. Ct. 1959), acknowledged

that the sale of a photographic negative, in the

ordinary course of its business, constituted

“substantial assistance” for aiding and abetting

liability because the defendant knew the buyer would

alter the picture and commit a tortious act. Thus,

“business as usual” provides no defense to aiding and

abetting liability.

6

Direct Sales Co. v. United States, 319 U.S. 703

(1943), provides further support because the

defendant mail-order drug manufacturer and

wholesaler should have known from the volume of the

narcotic it was selling to certain physicians that the

drug was being diverted for illegal use.

Mexico’s allegations fit the same systematic

pattern found sufficient in Direct Sales. Smith &

Wesson has made sales to straw sellers and others,

violative of federal law, with knowledge of the illicit

purposes that the sales facilitate within Mexico.

These claims deserve their day in court.

ARGUMENT

I.

SMITH & WESSON DOES NOT AND

CANNOT JUSTIFY ITS ONE-SIZE-FITS-ALL

APPROACH

TO

PLCAA’S

LIMITEDPURPOSE USE OF PROXIMATE CAUSE.

Smith & Wesson erroneously concludes, without

analysis, that there is but one proximate-cause

standard, that the applicable standard is federal in

nature, and that it requires a direct, one-step

relationship between the conduct and injury to incur

liability. Opening Br. 17-21. Based on that

formulation, it insists that the “‘central question’ is

thus ‘whether the alleged violation led directly to the

plaintiff’s injuries.’” Opening Br. 19 (quoting Anza v.

Ideal Basic Steel Supply Corp., 547 U.S. 451, 461

(2006)). Skipping the necessary steps entirely, Smith

& Wesson fails to undertake the analysis required to

determine the correct proximate-cause standard to

7

apply. This Court has insisted that the effort requires

exploring a statute’s text, legislative history, and who

the statute authorizes to sue. See Holmes, 503 U.S. at

267 (calling statutory history “key” and placing

emphasis on language borrowed from the Sherman

Act to adopt the same standard for RICO). Smith &

Wesson makes no such effort and presents the RICO

standard as if it were the singular federal standard

for all purposes.

A. PROXIMATE CAUSE IS A STATUTESPECIFIC CONCEPT.

Proximate cause does not embody the rigid onesize-fits-all inquiry that Smith & Wesson advances. It

is instead a “flexible concept that does not lend itself

to ‘a black-letter rule that will dictate the result in

every case.”’ Bridge v. Phoenix Bond & Indem. Co.,

553 U.S. 639, 654 (2008) (quoting Holmes, 503 U.S. at

272 n.20). It reflects “ideas of what justice demands,

or of what is administratively possible and

convenient.” Holmes, 503 U.S. at 268 (quoting W.

Keeton, D. Dobbs, R. Keeton, & D. Owen, Prosser and

Keeton on Law of Torts § 41, p. 264 (5th ed. 1984)); see

also Restatement (Third) of Torts: Liab. for Physical

& Emotional Harm §29 (2010).

It “has taken various forms; but courts have a

great deal of experience applying it, and there is a

wealth of precedent for them to draw upon in doing

so.” Lexmark, 572 U.S. at 133. Thus, as Justice Scalia

observed, different proximate-cause standards apply

even under RICO depending on which predicate act is

8

invoked. Holmes, 503 U.S. at 288 (Scalia, J.,

concurring) (explaining that the “degree of proximate

causality required to recover damages caused by

predicate acts of sports bribery … will be quite

different from the degree required for … transporting

stolen property”). A similar inquiry applies to PLCAA

because it, too, depends on a predicate violation to

authorize access to the courts in certain cases. See 15

U.S.C. § 7903(5)(A)(iii) (provision known as the

“predicate exception”).2

Mexico alleged violations of a number of federal

and state statutes in its Complaint, each of which fit

PLCAA’s predicate exception. See Pet. App. 27a-30a.

Smith & Wesson, however, has not briefed or argued

any proximate-cause standard applicable to any of

these statutes as it was obligated to do. That failure

provides no reason for this Court to undertake that

missing analysis under the party-presentation

principle. See Students for Fair Admissions, Inc. v.

President & Fellows of Harvard Coll., 600 U.S. 181,

342 n.21 (2023).

Generally, a proximate cause must only be

“substantial enough and close enough to the harm to

be recognized by law, [and] a given proximate cause

need not be, and frequently is not, the exclusive

2

The provision is known as the “predicate exception” “because its

operation requires an underlying or predicate statutory

violation.” Smith & Wesson Corp. v. City of Gary, 875 N.E.2d 422,

429-30 (Ind. Ct. App. 2007), trans. denied (2009).

9

proximate cause of harm.” Sosa v. Alvarez-Machain,

542 U.S. 692, 704 (2004). See also Keeton, § 41, at 268

(“If the defendant’s conduct was a substantial factor

in causing the plaintiff’s injury, it follows that he will

not be absolved from liability merely because other

causes have contributed to the result, since such

causes, innumerable, are always present.”).

Notably, proximate cause has little role to play in

intentional torts. When a party causes intentional

harm, liability follows even when that harm may have

been unlikely. Restatement (Third) of Torts § 33; see

also id. § 33 reporters’ note, cmt. F (listing cases

applying this principle); Restatement (Second) of

Torts § 435A (1965) (“A person who commits a tort

against another for the purpose of causing a

particular harm ... is liable for such harm if it results,

whether or not it is expectable.”). This approach

makes enormous good sense because intentional

“wrongful conduct is closely linked−temporally and

conceptually−to the plaintiff's harm.” Jill E. Fisch,

Cause for Concern: Causation and Federal Securities

Fraud, 94 Iowa L. Rev. 811, 832 (2009).

In addition, the defendant, through intentional

conduct resulting in harm, is self-evidently

blameworthy and will not produce overdeterrence. Id.

Thus, as one scholar put it, “[t]he rule of legal

(proximate) cause (scope of responsibility) for

intentional torts sweeps very broadly, almost to the

full reach of factual causation.” David W. Robertson,

The Common Sense of Cause in Fact, 75 Tex. L. Rev.

1765, 1773 n.30 (1997); cf. Keeton, § 8, at 37 n.27, 37

10

(for intended harms, “the law is astute to discover

even very remote causation”) (quoting Derosier v. New

England Tel. & Tel. Co., 130 A. 145, 152 (N.H. 1925)).

Proximate cause also involves a combined

question of law and fact generally committed to the

factfinder’s province and “subject to limited review.”

Holmes, 503 U.S. at 268. It is rarely an insuperable

barrier at the pleading stage, where the complaint’s

factual allegations must be taken as true and

construed in the light most favorable to the plaintiff.

Warth v. Seldin, 422 U.S. 490, 501 (1975); see also

Lexmark, 572 U.S. at 134 n.6 (entitling a plaintiff “an

opportunity to prove [allegations, taken as true, that

are sufficient to establish proximate cause.”]).

At this stage, proximate cause functions to

“eliminate[] the bizarre,” Jerome B. Grubart, Inc. v.

Great Lakes Dredge & Dock Co., 513 U.S. 527, 536

(1995), as well as claims “so attenuated that the

consequence is more aptly described as mere fortuity.”

Paroline v. U.S., 572 U.S. 434, 445 (2014) (citing

Exxon Co., U.S.A. v. Sofec, Inc., 517 U.S. 830, 838-39

(1996)). Yet, the injury Mexico claims is not a fortuity

or the product of an unforeseen superseding cause.

Sofec is instructive here. It endorses the view that the

superseding cause doctrine applies only where the

“injury was actually brought about by a later cause of

independent origin that was not foreseeable.” Sofec,

517 U.S. at 837 (quoting, with approval, 1 T.

Schoenbaum, Admiralty and Maritime Law § 5–3, pp.

165 (2d ed. 1994)). Sofec held that the harm at issue

11

was unforeseeable because it resulted from

unexpected superceding negligent conduct. Id. at 840.

Here, Mexico’s allegations support foreseeability,

as it alleges that the gun manufacturers chose to serve

a market known to supply the Mexican cartels. The

manufacturers’ intentional conduct had the known

and thus foreseeable consequence of causing Mexico’s

injury because the buyers in that market did what

everyone expected in moving the guns to Mexico for

criminal uses. The manufacturers’ conduct was thus a

foreseeable and not a superseding cause.

Proximate cause is also statute-specific. Lexmark,

572 U.S. at 133 (“[p]roximate-cause analysis is

controlled by the nature of the statutory cause of

action” and the “conduct the statute prohibits”); see

also Holmes, 503 U.S. at 272 n.20 (adopting a

directness standard because of “concerns set out in the

[statutory] text [of the RICO statute].”). As this

Court’s analysis made plain, the language adopted in

RICO that denotes causation, “by reason of,” were the

“same words” with the presumptive “same meaning

that courts had already given them” in the context of

the Sherman and Clayton antitrust statutes. Id. at

268. In all three instances, Congress chose a directinjury limitation because of the availability of treble

damages. Id. at 272. Although these cases involved

quite different statutory schemes and ideas about

statutory standing not at issue in this case, they

remain instructive for the idea they express that

statutes differ and proximate cause then likewise

differs. Smith & Wesson errs in telling this Court that

12

the same proximate-cause standard of the laws

examined in those cases is the federal standard.

In fact, in contrast to and completely refuting

Smith & Wesson’s claim of a single existing federal

standard, this Court held that the Federal Employers’

Liability Act, 45 U.S.C. § 51 et seq., utilizes a “relaxed

standard of causation” when compared to commonlaw

tort

litigation

reflecting

Congress’s

“‘humanitarian’ and ‘remedial goal[s]’” in prioritizing

the safety of railroad workers. CSX Transp., 564 U.S.

at 692 (citation omitted; brackets in orig.). The

analysis in both Holmes and CSX focuses heavily on

legislative purpose to perform a critical role in

determining

the

applicable

proximate-cause

standard. That purpose defines the scope of the causal

relationship and cabins both the class of persons

protected by an act and the types of harms for which

liability is imposed. Cf. Keeton, § 53 at 358.

B. PLCAA Has No Independent Proximate

Cause

Standard,

But

Instead

Incorporates the Standard Imposed by

the Statute Violated.

The fundamental purpose of proximate cause is to

determine “whether the conduct in question creates

any liability” for injuries that subsequently occur.

Sandra F. Sperino, Discrimination Statutes, the

Common Law, and Proximate Cause, 2013 U. Ill. L.

Rev. 1, 5 (2013). Proximate cause “is an element of the

cause of action under [a] statute.” Lexmark, 572 U.S.

at 134 n.6 (emphasis added). Statutes that create

causes of action to which liability attaches have a

13

proximate-cause

requirement,

whether

the

requirement is explicitly stated or not. CSX Transp.,

564 U.S. at 708.

PLCAA itself creates no liability or cause of

action. It is an exceedingly unusual statute. Congress

enacted it because legislators objected to the grounds

that some had asserted against the gun industry and

gun dealers. See Hillel Y. Levin & Timothy D. Lytton,

The Contours of Gun Industry Immunity: Separation

of Powers, Federalism, and the Second Amendment,

75 Fla. L. Rev. 833, 841 (2023). Compare, e.g., Ileto v.

Glock Inc., 349 F.3d 1191, 1194 (9th Cir. 2003), cert.

denied sub. nom., China N. Indus. Corp. v. Ileto, 543

U.S. 1050 (2005) (permitting a case to go forward prePLCAA), with Ileto v. Glock, Inc., 565 F.3d 1126, 1135

(9th Cir. 2009), cert. denied, 560 U.S. 924 (2010)

(finding the same case foreclosed by PLCAA).

Congress explained its view in PLCAA’s findings:

The liability actions commenced or

contemplated by the Federal Government,

States, municipalities, and private interest

groups and others are based on theories

without foundation in hundreds of years of the

common law and jurisprudence of the United

States and do not represent a bona fide

expansion of the common law. The possible

sustaining of these actions by a maverick

judicial officer or petit jury would expand civil

liability in a manner never contemplated by

14

the framers of the Constitution, by Congress,

or by the legislatures of the several States.

15 U.S.C. § 7901(a)(7).

In service of that purpose, PLCAA prohibits a

“qualified civil liability action” from being maintained

“in any Federal or State court.” 15 U.S.C. § 7902(a). It

defines a “qualified civil liability action” as:

a civil action or proceeding ... brought by any

person against a manufacturer or seller of a

[firearm distributed in interstate or foreign

commerce] ... for damages, punitive damages,

injunctive or declaratory relief, abatement,

restitution, fines, or penalties, or other relief,

resulting from the criminal or unlawful

misuse of a [firearm distributed in interstate

or foreign commerce] by the person or a third

party.

15 U.S.C. § 7903(5)(A).

Although it permitted certain common-law causes

of action, see, e.g., 15 U.S.C. § 7903(5)((A)(ii) (“an

action brought against a seller for negligent

entrustment or negligence per se”), enactment of

PLCAA in 2005 had the effect of terminating certain

other previously upheld common-law causes of action.

See Ileto, 565 F.3d at 1135.

At the same time, however, Congress chose to

respect liability generated by legislative choices in an

exception to its general prohibition. Under this

15

“predicate exception,” the prohibition on qualified civil

liability actions disappears when a plaintiff

adequately alleges that a “manufacturer or seller of

[firearms transported in interstate or foreign

commerce] knowingly violated a State or Federal

statute applicable to the sale or marketing of

[firearms], and the violation was the proximate cause

of the harm for which relief is sought.” 15 U.S.C. §

7903(5)(A)(iii). The statutory violation opens the door,

then, to all potential claims. Notably, PLCAA does not

limit the liability standards a statute may adopt.

Nor does PLCAA adopt a particular version of

proximate cause. Instead, the predicate exception

uses the term “proximate cause” to require that the

statutory violation be connected to the underlying

harm. In this sense, PLCAA’s use of proximate cause

serves a purpose similar to the connective tissue that

“fairly traceable” provides for purposes of

constitutional standing. See, e.g., Clapper v. Amnesty

Int’l USA, 568 U.S. 398, 413 (2013) (holding

speculative harm insufficient to support the “fairly

traceable” element of standing). In PLCAA, Congress

used “proximate cause” to tie the statutory violation

to the harm. Although proximate cause demands a

higher threshold than fairly traceable does, see

Lexmark, 572 U.S. at 134 n.6, the purpose it serves,

allowing an examination of the statutory basis for a

violation and the alleged injury to open access to the

courts, does not require a demanding examination at

this stage of the proceedings.

16

Instead, it is the statute violated that supplies the

proper proximate-cause standard. In that respect,

PLCAA borrows a proximate-cause standard from

other statutes in much the way that RICO utilizes

different “degree[s] of proximate causality” depending

on different predicate acts. Holmes, 503 U.S. at 288

(Scalia, J., concurring).

In that sense, the use of proximate cause in

PLCAA incorporates by reference the applicable

standard from another statute. When the statute is

state law, courts have used the proximate-cause

standard applicable to that statute with careful

attention to the closeness or remoteness of the causal

connection. See, e.g., Soto v. Bushmaster Firearms

Int’l, LLC, 202 A.3d 262, 288 (applying the

longstanding proximate-cause standard for the

Connecticut statute at issue and noting that in a prior

case the harms alleged from gun violence were “too

remote and derivative” to sustain a statutory claim),

cert. denied sub. nom. Remington Arms Co., LLC, v.

Soto, 140 S. Ct. 513 (2019). In instances like that,

Smith & Wesson’s misguided rule would displace

state law entirely when PLCAA explicitly defers to

state statutory law.

Although the Complaint in this case alleged a host

of state law violations that are not before this Court,

Amici would like to focus this Court’s attention on one

state-law violation because it exemplifies Smith &

Wesson’s error and explains why its proposed

proximate-cause standard is unworkable as one that

would apply to every case qualifying under the

17

predicate exception. More critically, it plainly refutes

Smith & Wesson’s claim that a federal standard

applies. To be clear, if there is applicable state

statutory law, the operative section of PLCAA is

without effect, and a State may impose the exact same

liability that PLCAA would otherwise prohibit.3

Take, for example, Count Eight of Mexico’s

complaint, which alleged that Smith & Wesson

violated the Massachusetts Consumer Protection Act,

Mass. Gen. Laws c. 93A, “by marketing that

emphasized the ability of civilians to use Smith &

Wesson assault rifles in unlawful, military-style

attacks.” Pet. App. 193a, at ¶ 550. Under

Massachusetts law, proximate cause “is a required

element of a successful G.L. c. 93A claim.” Aspinall v.

Philip Morris Cos., Inc., 813 N.E.2d 476, 491 (Mass.

2004). However, Massachusetts takes a different

approach to proximate cause than Smith & Wesson

claims as its purported all-purpose federal standard.4

Massachusetts

employs

a

“reasonableforeseeability-of-harm” standard that examines all

the relevant circumstances. Flood v. Southland Corp.,

616 N.E.2d 1068, 1075 (Mass. 1993) (citations

omitted); see also Whittaker v. Saraceno, 635 N.E.2d

3

4

This sentence is equally true of a federal law violation.

As explained above, there is no generic federal standard

because the applicable proximate cause standard depends on the

nature of the statutory cause of action. See Lexmark, 572 U.S. at

133.

18

1185, 1187 (Mass. 1994) (citing 4 F. Harper, F. James,

Jr., & O. Gray, Torts § 20.5, at 136–137 (2d ed. 1986).

Cf. Restatement (Third) of Torts § 29; Dan B. Dobbs et

al., The Law of Torts § 198 (2d. ed. 2024)). Relevantly,

it further holds that prior similar criminal acts

constitute a relevant circumstance for foreseeability

purposes and that their absence is not conclusive for

a defendant’s lack of liability. Whittaker, 635 N.E.2d

at 1188.

In Massachusetts’s usage, as in other States,

foreseeability is “‘interwoven with our feelings about

fair and just limits to legal responsibility.’” Id. at 1187

(quoting 4 Harper, § 20.5, at 136-37). Still, as in other

States, Massachusetts employs its foreseeability

standard as leavened by “considerations of policy and

pragmatic judgment.” Doull v. Foster, 163 N.E.3d 976,

983 (2021) (citation omitted). Even where the state

cause of action is later dismissed, the predicate

exception’s plain language renders a sufficient

pleading enough to open the courthouse door to the

lawsuit.

Because PLCAA imposes no independent

proximate cause standard but adopts that of the

underlying statutory violation, it is useful to consider

a recent example of the proximate-cause analysis used

in Massachusetts courts. In this case, the owners of a

building sued a kitchen appliance repair company

over a fire in a restaurant housed in their building. An

employee of the defendant repair company had told

the restaurant’s kitchen staff that he had repaired

their fryer. The kitchen staff relied upon the

19

defendant’s false representation that a fryer had been

repaired, used it, and 12 hours later the faulty fryer

caused a fire that damaged the building. The court

held that proximate cause was satisfied under both

the negligence and consumer protection law causes of

action. Hyannis Anglers Club, Inc. v. Harris Warren

Com. Kitchens, LLC, 78 N.E.3d 784, 790 (2017). The

multi-step approach taken in the case demonstrates

that the state-based cause of action in this case plainly

satisfies the incorporated proximate cause standard

for PLCAA’s predicate exception.

Mexico satisfies the Massachusetts reasonable

foreseeability standard. It has alleged that a “fairly

small percentage of their dealers sell virtually all

crime guns recovered in Mexico” and specifically to

cartel buyers. Pet. App. 44a, 54a-70a. Not only do they

know that these guns end up in the cartels’ hands, but

that have relied heavily on these sales through

systematic exploitation of those distribution channels.

Id. at 44a-46a, 80a-81a. These markets provide

manufacturers with significant revenue. Id. at 49a,

141a-145a. The allegations support intentional

conduct with known consequences and satisfy the

reasonable-foreseeability

standard

that

Massachusetts employs.

II. EVEN IF A DIRECTNESS STANDARD

WERE

APPLIED

AND

DISPLACED

FORESEEABILITY, IT WOULD PROVIDE

NO BASIS FOR DISMISSAL UNDER PLCAA.

Because PLCAA provides no cause of action, it

cannot impose an independent proximate cause

20

requirement.

Instead,

its

predicate-exception

provision must be read to incorporate the proximatecause standard of the violated statute. Yet, even if one

were to apply the direct-relation test that Smith &

Wesson advocates, Mexico satisfies the test.

Mexico has alleged a substantial, non-derivative

injury that is not just reasonably foreseeable, but also

is necessarily and directly connected to the gun

manufacturers’ conduct in marketing and selling its

products with an eye to the Mexican market, and thus

plausibly bears “some direct relation between the

injury asserted and the injurious conduct alleged.”

Holmes, 503 U.S. at 268. Nothing more is necessary,

even under that standard.

To be clear, Mexico alleged numerous federal

violations,

“including

violations

of

statutes

prohibiting sales to straw purchasers, sales without a

license, and exporting guns without a permit.” Mexico

Br. 39. These laws seek to prevent criminals from

obtaining guns. Their violation plainly creates a tight

causal chain to the harm that Mexico suffered. As a

result, it was not only reasonably foreseeable that the

harm would befall Mexico, but the purposeful use of

those channels of commerce, such as sales to known

red-flag dealers, renders the causal chain much more

than foreseeable, even if that should suffice as a direct

causal connection. It is not as though the guns’ illegal

entry into Mexico was inadvertent; as alleged, it is but

the inexorable result of the gun manufacturers’

marketing and distribution actions.

21

A. Even the Directness Test Involves

Flexibility and Consideration of the

Relevant Circumstances.

Smith & Wesson emphasizes the “first step” that

is sometimes part of the “general tendency in these

cases.” See Hemi Group, LLC v. City of New York, 559

U.S. 1, 10 (2010) (cleaned up). But a “general tendency

is not the same as a hard and fast rule that dictates

the outcome in every case.” City of Miami v. Wells

Fargo & Co., 923 F.3d 1260, 1273 (11th Cir. 2019),

cert. granted, judgment vacated sub nom. Wells Fargo

& Co. v. City of Miami, 140 S. Ct. 1259 (2020). Even

so, “[w]hat falls within that ‘first step’ depends in part

on the ‘nature of the statutory cause of action,’” and

an assessment “‘of what is administratively possible

and convenient.’” City of Miami, 581 U.S. at 203.

B. A Causal Chain Can Always Be

Creatively Extended, But that Does Not

Per Se Deny Liability.

Smith & Wesson ignores the flexibility built into

that first-step analysis and then devises eight links in

the causal chain. Opening Br. 22. That formulation

overstates the length of the causal chain to claim as

many steps as possible. In the same fashion, the act of

breathing can become a multi-step enterprise,

involving (1) opening one’s mouth, (2) contracting the

diaphragm and intercostal muscles, (3) inhaling air,

(4) relaxing the same muscles, (5) exhaling, and (6)

closing one’s mouth. It is still one breath.

22

This Court held that the direct-relation test met in

Lexmark, even though the causal chain went well

beyond a first step. Static Control, the plaintiff for this

aspect of the case, was neither a Lexmark customer

nor competitor in this Lanham Act lawsuit. The

plaintiff made a component microchip part that

enabled Lexmark’s competitors to refill used ink

cartridges from Lexmark’s laser-printer customers.

When Lexmark warned customers against sending

empty cartridges to anyone but Lexmark, it affected

Static Control’s customers who then no longer bought

as many microchips.

Mexico is not a derivative plaintiff as Static

Control was, which makes Smith & Wesson’s

directness complaint even more inapt. Still, under

Smith & Wesson’s approach, Lexmark would have

involved too many steps in the causal chain to satisfy

direct proximate cause: (1) a disparaging statement

about selling the cartridges to anyone else, (2) the

statement’s distribution to Static Control’s clients’

potential customers, (3) the statement’s receipt by an

audience, (4) the audience believing it, (5) the

audience returning the empty cartridge to Lexmark,

rather than selling it to a remanufacturer who used

Static Control’s products, (6) the consequent loss of

business to the remanufacturer; and (7) the

subsequent loss of business to Static Control. Yet, this

Court took no issue with this lengthy causal chain

when examining proximate cause.

Lexmark recognized that “Static Control’s

allegations therefore might not support standing

23

under a strict application of the general tendency not

to stretch proximate causation beyond the first step,”

but held that the absence of a discontinuity and a 1:1

relationship from the loss of sales took speculation out

of the equation. 572 U.S. at 139. For that reason, this

Court invoked the principle that “‘[w]here the injury

alleged is so integral an aspect of the [violation]

alleged, there can be no question’ that proximate

cause is satisfied.” Id. (quoting Blue Shield of Va. v.

McCready, 457 U.S. 465, 479 (1982)).

By the same token, Mexico’s significant and

effective domestic limits on gun sales and the

prevalence of guns obtained from the defendant gun

manufacturers through straw sales and other devices

makes speculation about the causal connection

unnecessary. Mexico’s claim of proximate cause

appears stronger than Static Control’s claim.

Moreover, as in Lexmark, consideration of the

underlying statutory violations alleged, such as the

prohibition on straw sales, PLCAA erects no obstacle

to this action and, indeed, contemplates the

involvement of third parties in the causal chain.

III. THE ORDINARY COURSE OF BUSINESS

SUPPLIES NO DEFENSE TO AIDING-ANDABETTING LIABILITY.

Smith & Wesson argues that its “business as

usual” practices immunize it from aiding-andabetting liability. Opening Br. 32-39. As with

proximate cause, the gun manufacturer takes a facile

position on a complex and nuanced issue. As this

Court recently explained, employers are generally

24

accountable for an employee’s wrongdoing committed

in the ordinary course of business. Bartenwerfer v.

Buckley, 598 U.S. 69, 82 (2023). Similarly, a

partnership becomes liable for a partner’s wrongful

act taken with authority or in the ordinary course of

business. Id. These examples make plain that

“business as usual” is hardly a talisman that

forecloses liability. It can, rather, serve as the basis

for liability.

To be sure, this Court has asked courts to be

mindful that “if aiding-and-abetting liability were

taken too far, then ordinary merchants could become

liable for any misuse of their goods and services, no

matter how attenuated their relationship with the

wrongdoer.” Twitter, 598 U.S. at 489. Twitter did not

absolve aiding and abetting liability because it

followed a consistent business model. Rather it

understood that a business that knows it is

facilitating criminal activity may incur liability. See

id. at 488−89; cf. Camp v. Dema, 948 F.2d 455, 459

(8th Cir. 1991).

Mexico’s complaint alleges facts that indicate that

Smith & Wesson had the type of knowledge of and

involvement in defendant gun sellers’ misconduct,

which goes beyond mere “business as usual.” See

Resp. Br. 15-16, 19, 25. Its detailed allegations fully

fit the requirements for aiding and abetting liability,

when taken as true, and this matter should not be

resolved at the pleading stage as Smith & Wesson

requests. The allegations make plain that the

consequences to Mexico of Smith & Wesson’s behavior

25

was not inadvertent but intentional. The pleading

satisfies the mens rea requirement of aiding and

abetting liability through its allegations about Smith

& Wesson’s conduct.

A. Aiding and Abetting Liability Was

Developed to Address Misconduct Like

that Alleged Here.

Aiding and abetting boasts ancient roots in

criminal law. Cent. Bank of Denver, N.A. v. First

Interstate Bank of Denver, N.A., 511 U.S. 164, 181

(1994). It is well established that “knowing aid to

persons committing federal crimes, with the intent to

facilitate the crime,” constitutes a criminal act. Id.

(quoting Nye & Nissen v. United States, 336 U.S. 613,

619 (1949)). Thus, federal law provides that a person

who “aids, abets, counsels, commands, induces, or

procures” a federal offense is “punishable as a

principal.” 18 U.S.C. § 2(a). It attaches, as Judge

Learned Hand wrote, to conduct where the defendant

“in some sort associate[s] himself with the venture,

that he participate[s] in it as in something that he

wishes to bring about, that he seek[s] by his action to

make it succeed.” United States v. Peoni, 100 F.2d 401,

402 (2d Cir. 1938).

Aiding and abetting liability is also a familiar

aspect of civil law, not just in the United States, but

“well-established” and “frequently invoked” as well as

an aspect of international law, particularly

throughout “the second half of the twentieth century

and into this century.” Khulumani v. Barclay Nat’l

26

Bank Ltd., 504 F.3d 254, 270 (2d Cir. 2007)

(Katzmann, J., concurring). As this Court recognized

in Twitter, an influential and well-regarded opinion of

the District of Columbia Circuit, Halberstam,

provides significant guidance in applying aiding and

abetting in the civil context. Twitter, 598 U.S. at 484.

In Halberstam, the D.C. Circuit “undertook an

extensive survey of the common law, examining a

series of state and federal cases, the Restatement

(Second) of Torts, and prominent treatises that

discussed secondary liability in tort.” Id. at 486 (citing

Halberstam, 705 F.2d at 476–78, 481–86). In fact, the

Halberstam opinion provides valuable insight that

should guide this Court.

One case, in particular, reviewed with approval in

Halberstam, provides ample precedent to negate

Smith & Wesson’s claim that business as usual

exonerates. In the case, a book company was held

potentially liable for selling a “model’s picture to a

company with the knowledge the company would (as

it did) alter and use the picture to defame the model.”

Id. at 482 (describing Russell, 183 N.Y.S.2d 8). The

sale, accomplished in the normal course of the

defendant book company’s business, constituted

“substantial assistance” for liability because the

defendant knew of the “buyer's intent to alter and

publish the picture.” Id.

Because Smith & Wesson purports to defend itself

by reference to ordinary business activities, it is useful

to delve deeper into the facts in Russell. The plaintiff

model had agreed in an oral contract to pose for well-

27

known fashion photographer Richard Avedon for a

single, full-page New York Times advertisement for

Marboro Books that would also be duplicated as a

poster to appear in bookstores. Russell, 183 N.Y.S.2d

at 16. The model also understood that the photograph

would be for that use alone, yet she signed a release

that consented to unrestricted use without any need

for preapproval. Id. at 16, 18. The tasteful

advertisement placed the model in bed reading an

educational book and bore the caption, “For People

Who Take Their Reading Seriously.” Id. at 16.

However, Marboro subsequently sold a negative of the

photograph to a third party who sold bedsheets and

had a reputation for offensive advertising. Id. The

third party altered the photograph so that it appeared

that the model was “a willing call girl waiting to be

used by a stranger whetting his sexual appetite” and

was published in magazines with circulation in the

millions. Id. at 17.

The court found no breach of contract in this course

of events and dismissed that claim because of the

written, signed release. Id. at 23. Nonetheless, the

court held that “it does not follow that the consent

signed by the plaintiff goes beyond its wording so as

to exculpate, as a matter of law, the dissemination of

all types of altered pictures or of libelous material.” Id.

at 28. Because the plaintiff alleged that “Marboro had

knowledge of the plaintiff's personal and professional

standing and of the objectionable nature of [bedsheet

manufacturer’s] advertisements and that Marboro

made the sale in order to enable [the manufacturer] to

retouch the photograph and art work and to publish

28

the altered picture with reading matter that libeled

the plaintiff,” the plaintiff had pleaded a valid cause

of action, adopting the “substantial assistance”

principle described in the Restatement of Torts, id. at

31, and now known as aiding and abetting liability.

It therefore did not matter in the surviving action

for libel and breach of privacy, the proof of which the

court recognized remained to be seen, id., that

Marboro Books acted consistently with its business

model and had a valid contract, because it knowingly

made it possible for another to commit a tort.

Another case described in Halberstam’s survey

provides further support for Mexico’s approach to

aiding and abetting. Introducing the example,

Halberstam correctly noted that the “contributing

activity itself need not be so obviously nefarious as

cheering a beating or prodding someone to drive

recklessly” to qualify as aiding and abetting. 705 F.2d

at 482. The trenchant example was a case in which

students engaged in “horse play” by “throwing wooden

blackboard erasers, chalk, cardboard drum covers,

and, in one instance, a ‘coke’ bottle, at each other,”

with no intent to injure one another and while

awaiting the arrival of a music teacher who was late

for class. Keel v. Hainline, 331 P.2d 397, 398−99 (Okla.

1958) (cited in Halberstam, 705 F.2d at 482)).

The plaintiff, who was not participating in the

activity but studying at her desk, was hit by an errant

eraser that shattered her glasses and resulted in the

loss of an eye. Id. Before the Oklahoma Supreme

29

Court, a student argued against being treated as

having aided and abetted the assault because he had

merely retrieved thrown erasers and handed them

back to other defendants who threw them again. Id.

at 400. The court rejected his argument, holding that

the student aided and abetted the wrongful throwing

by procuring and supplying articles to be thrown. Id.

Moreover, it was deemed “immaterial” that he did not

encourage throwing by the particular student who

injured the plaintiff or supply an eraser to that

student, id., because his actions nonetheless had

“substantially encouraged the wrongful activity that

resulted in the injury.” Halberstam, 705 F.2d at 482

(characterizing Keel, 331 P.2d at 400).

Keel and its endorsement in Halberstam

demonstrate

that

knowingly

supplying

the

instrument that could cause injury satisfies aiding

and abetting liability because the knowledge of the

reasonably foreseeable consequence that someone

could be harmed provides a sufficient engagement in

the enterprise, particularly given Smith & Wesson’s

motivating positive interest in continuing sales that

have the consequences that Mexico suffered. Cf. Direct

Sales, 319 U.S. at 707−08.

In the instant matter, Mexico alleges that Smith &

Wesson not only knowingly supplied far more deadly

weapons than erasers but adjusted its marketing and

efforts to take advantage of the market that served

the cartels. See, e.g., Pet. App. 84a-85a. This action,

even though it furthers Smith & Wesson’s ordinary

business interests, constitutes the type of

30

“‘affirmative act’” “‘with the intent of facilitating the

offense’s commission’” that this Court said was

essential in Twitter. 598 U.S. 490 (quoting Rosemond

v. United States, 572 U.S. 65, 71 (2014)). The upshot

is that Mexico has pleaded enough to move to

discovery.

Actions like those alleged by Mexico comfortably

fit within our understanding of aiding and abetting

liability, especially because the concept of joint

responsibility has its roots in concurrent liability. As

Halberstam explains, full concurrent liability for

concerted actions first developed as a sensible

response to various related actions that were properly

viewed as an indivisible whole. Halberstam, 705 F.2d

at 476-77. Then, that type of “vicarious liability”

became applicable to more subtle relationships

between the defendants. Id. at 477. This variety of

liability took three forms: (1) a conspiracy united by a

common design; (2) providing substantial assistance

or encouragement in the breach of a duty; or, (3)

providing substantial assistance for a tortious act

when the co-conspirator separately breached a duty.

Id. These actions became known as conspiracy

because the more remote person held liable promoted

means or purposes that were tortious. Id.

Aiding and abetting liability thus took on a

somewhat different coloration. A third party commits

the wrongful act that results in injury, but the aider

and abettor is aware of playing a role in that wrongful

act and nonetheless knowingly, willingly, and

substantially assists its commission, demonstrating

31

an intent to facilitate the misconduct. Id. In

conspiracy, the person “agree[s] to participate in a

wrongful activity.” Id. at 478. In aiding and abetting,

there is no necessary agreement to participate but

there must be a knowing provision of substantial

assistance in a supportive relationship. Id. That

assistance can take the form of encouragement that

results in a wrongful act, such as a suggestion to a

driver that a new car be tested for its speed and

capabilities and doing so results in injury when a

person was struck by the recklessly driven vehicle,

thereby imposing liability as well on the encourager.

Id. at 481-82 (describing the facts in Cobb v. Indian

Springs, Inc., 522 S.W.2d 383 (Ark. 1975)).

B. Mexico’s

Allegations

Fit

the

Requirements for Aiding and Abetting

Liability.

Mexico has leveled allegations that support its

action. In short, Mexico’s pleading has alleged that

the defendant gun manufacturers design, market, and

distribute their guns to enable their purchase by the

cartels. See Pet. App. 43a-50a, 54a-71a, 75a-76a, 80a,

81a-83a, 86a, 93a-102a, 104a-122a, and 124a. They do

so, Mexico contends, in large quantities, thereby

facilitating an illegal Mexican market that generates

significant profit for the manufacturers. Pet. App.

305a, 141a-142a.

Direct Sales provides important lessons in

assessing these allegations. The defendant before this

Court in that case was a mail-order drug

manufacturer and wholesaler. Along with other

32

defendants, it was convicted of violating the law in the

distribution of narcotics. Direct Sales, as it was

authorized to do, distributed morphine sulfate, among

other prescription drugs, to physicians, who typically

ordered no more than 400 one-quarter grain tablets

annually for legitimate use. Direct Sales, 319 U.S. at

706. One South Carolina physician, practicing in a

small town, was ordering such large quantities that

he was meeting the average annual distribution on a

daily basis. Id. Despite warnings from the Bureau of

Narcotics about illicit use, Direct Sales continued to

supply that one physician with an ever-increasing

quantities. Id. at 707−08.

This pattern of conduct supported conviction

because the drug company, “working in prolonged

cooperation with a physician’s unlawful purpose to

supply him with his stock in trade for his illicit

enterprise, … not only knows and acquiesces, but joins

both mind and hand with him to make its

accomplishment possible.” Id. at 713. Nor did it

matter that the cooperation was tacit through the

supplier’s actions, rather than the product of an

express written agreement. Id. at 714.

Mexico’s allegations fit the same systematic

pattern as were found sufficient in Direct Sales. Smith

& Wesson has joined in mind and hand with straw

sellers and others to infiltrate guns for illicit purposes

into its sovereign territory. Mexico’s claims deserves

their day in court.

33

CONCLUSION

For the foregoing reasons, this Court should affirm.

Respectfully submitted,

JAMES D. GOTZ

HAUSFELD LLP

One Marina Park Drive

Suite 1410

Boston, MA 02210

(617) 207-0600

jgotz@hausfeld.com

ROBERT S. PECK

Counsel of Record

CENTER FOR CONSTITUTIONAL

LITIGATION, PC

1901 Connecticut Avenue, NW

Suite 1101

Washington, DC 20009

(202) 944-2874

robert.peck@cclfirm.com

Counsel for Amici Curiae

JANUARY 2025