Reply Brief — Thomas Keller, Petitioner v. United States

No. 25-7141

I N T HE SU P REME CO U RT O F T HE U N I T ED STAT ES

________________________________

T HO MAS K EL L ER,

Petitioner ,

v.

UNITED STATES,

________________________________

Respondent.

On Petition for a Writ of Certiorari to the

United States Court of Appeals for the Ninth Circuit

________________________________

R EP LY BRI EF F OR P ET I T I O N ER

JODI LINKER

Federal Public Defender

Northern District of California

TODD M. BORDEN *

Assistant Federal Public Defender

450 Golden Gate Avenue, 19th Floor

San Francisco, California 94102

(415) 436-7700

* Counsel of Record for Petitioner

TABLE OF CONTENTS

TABLE OF AUTHORITIES ......................................................................................... II

REPLY BRIEF ............................................................................................................... 1

I.

THE QUESTION PRESENTED MERITS PLENARY REVIEW. ................................ 2

II.

ALTERNATIVELY, THE COURT SHOULD HOLD THIS PETITION PENDING

DISPOSITION OF PHEASANT V. UNITED STATES, NO. 25-6911. .............................. 11

CONCLUSION............................................................................................................. 12

i

TABLE OF AUTHORITIES

Federal Cases

Alaska Airlines, Inc. v. Brock,

480 U.S. 678 (1987) ............................................................................................... 11

Barr v. American Association of Political Consultants,

591 U.S. 610 (2020) ............................................................................................... 11

Bass v. United States,

324 F.2d 168 (8th Cir. 1963) ................................................................................... 9

Gonzalez v. Oregon,

546 U.S. 243 (2006) ................................................................................................. 6

Loving v. United States,

517 U.S. 748 (1996) ............................................................................................. 1, 7

Ruan v. United States,

597 U.S. 450 (2022) ................................................................................................. 9

Sessions v. Dimaya,

584 U.S. 148 (2018) ................................................................................................. 5

Touby v. United States,

500 U.S. 160 (1991) ..................................................................................... 1, 2, 4, 8

United States v. Clerfe,

___F.4th___, No. 24-2116, 2026 WL 2294460 (3d Cir. Aug. 10, 2026) ................... 3

United States v. Cooper,

750 F.3d 263 (3d Cir. 2014) .................................................................................... 3

United States v. Grimaud,

220 U.S. 506 (1911) ............................................................................................. 1, 7

United States v. Moore,

423 U.S. 122 (1975) ............................................................................................. 1, 7

United States v. Nichols,

775 F.3d 1225 (10th Cir. 2014) ............................................................................... 3

United States v. Pheasant,

129 F.4th 576 (9th Cir. 2025) ............................................................... 2, 3, 4, 8, 11

ii

Federal Rules and Statutes

21 C.F.R. § 1306.04 ............................................................................ 4, 5, 6, 7, 8, 9, 10

8 U.S.C. § 1325 ............................................................................................................. 7

21 U.S.C. § 811 ............................................................................................................. 5

21 U.S.C. § 812 ............................................................................................................. 5

21 U.S.C. § 821 ................................................................................. 1, 4, 5, 6, 9, 10, 11

21 U.S.C. § 822 ........................................................................................................... 10

21 U.S.C. § 823 ............................................................................................................. 5

21 U.S.C. § 824 .............................................................................................................. 5

21 U.S.C. § 841 ............................................................................................. 8, 9, 10, 11

21 U.S.C. § 871 ................................................................................. 1, 4, 5, 6, 9, 10, 11

Other Authority

Paul J. Larkin, Jr., Regulation, Prohibition, and Overcriminalization: The Proper

and Improper Uses of the Criminal Law, 42 Hofstra L. Rev. 745 (2014) ............... 3–4

iii

REPLY BRIEF

This case presents the question that Touby v. United States, 500 U.S. 160

(1991), reserved thirty-five years ago and that the government still cannot answer:

Whether Congress must do more than articulate an intelligible principle before

delegating to the Executive the power to define criminal conduct. The government

does not dispute that circuit after circuit has applied the intelligible-principle test

only after acknowledging that a heightened standard might apply and inviting this

Court’s guidance. The Ninth Circuit, however, has adopted a more aggressive

course, holding that no heightened standard applies even to criminal delegations.

The continuing uncertainty about this important question is reason enough to grant

review.

The government’s merits defense is deeply flawed. It leans overwhelmingly on

Touby, but Touby upheld a delegation constrained by express statutory findings,

enumerated factors, and substantive criteria. The portions of the Controlled

Substances Act (CSA) that supported the delegation here—21 U.S.C. §§ 821 and

871(b)—supply no such guideposts, a point the government does not contest. Its

reliance on United States v. Moore, 423 U.S. 122 (1975), Loving v. United States,

517 U.S. 748 (1996), and United States v. Grimaud, 220 U.S. 506 (1911), is equally

unavailing, since none of those decisions addressed a nondelegation challenge to a

criminal statute so lacking any legislative standard for the conduct it criminalizes.

Nor do the government’s two vehicle objections hold up. Keller’s convictions

rested squarely on 21 C.F.R. § 1306.04(a)’s “legitimate medical purpose” standard,

as the indictment, jury instructions, and the Ninth Circuit’s opinion confirm. In

1

addition, severance poses no problem: This Court can leave intact the statute’s

exception for licensed physicians, and should simply sever the standardless

delegation that allowed the Attorney General to expand the statute’s criminal reach

through a regulation. This case is a clean vehicle for deciding a question this Court

has reserved in Touby and the courts of appeals have repeatedly asked it to answer.

At minimum, if the Court grants review in Pheasant v. United States, No. 25-6911,

which presents the same nondelegation question, this petition should be held

pending the Court’s resolution of that case.

I.

The question presented merits plenary review.

Thirty-five years ago, this Court in Touby expressly reserved whether the

nondelegation doctrine demands something more than an intelligible principle

when Congress delegates authority to define criminal conduct. Touby, 500 U.S. at

165–66. In the interim, circuit after circuit has applied the intelligible-principle test

while explicitly calling for this Court’s guidance. See Pet. 6–8. The Ninth Circuit

has now broken from that careful approach, squarely holding that no heightened

standard applies even in the criminal context. Pet. App. 22a; United States v.

Pheasant, 129 F.4th 576, 583 (9th Cir. 2025). The question affects numerous federal

prosecutions every year and warrants this Court’s resolution.

A. The government concedes the question presented has never been resolved,

acknowledging that this Court “stated in Touby that it is ‘not entirely clear as to

whether more specific guidance is in fact required’ when Congress delegates

authority ‘to promulgate regulations that contemplate criminal sanctions.’” Brief in

Opposition (BIO) 13 (quoting Touby, 500 U.S. at 165–66). The government does

2

not—because it cannot—cite a single decision in which this Court has held

expressly that the intelligible-principle test is the correct and exclusive standard for

criminal delegations.

Courts of appeals have taken differing approaches in the face of that

uncertainty. The Third Circuit has declined to hold that heightened standard

applies to criminal delegations, “even as the intelligible principle test withers,”

“unless and until” that test “is overruled” by this Court. United States v. Clerfe,

___F.4th___, No. 24-2116, 2026 WL 2294460, at *6 (3d Cir. Aug. 10, 2026); see also

United States v. Cooper, 750 F.3d 263, 271 (3d Cir. 2014). The Tenth Circuit has

done the same. United States v. Nichols, 775 F.3d 1225, 1232 (10th Cir. 2014), rev’d

on other grounds, 578 U.S. 104 (2016).

The Ninth Circuit has charted a more aggressive course. It affirmatively held—

in Pheasant and again here—that the intelligible-principle test is the only

applicable standard, even in the criminal context. That square resolution of a

question this Court reserved, and on which multiple circuits have explicitly sought

guidance, warrants review.

The question presented is not academic. Federal criminal law increasingly relies

on executive regulations to define the scope of liability. Physicians, pharmacists,

firearms dealers, importers, environmental engineers, and countless others face

potential felony charges for conduct that falls outside regulatory safe harbors

promulgated by agencies with broad, loosely constrained rulemaking authority. See,

e.g., Paul J. Larkin, Jr., Regulation, Prohibition, and Overcriminalization: The

Proper and Improper Uses of the Criminal Law, 42 Hofstra L. Rev. 745, 749–53

3

(2014). The Controlled Substances Act alone generates numerous prosecutions each

year. Whether a registered doctor is practicing medicine or committing a federal

crime turns entirely on whether the prescription was issued “for a legitimate

medical purpose” and “in the usual course of professional practice”—standards

defined solely by § 1306.04(a). The importance of the question, combined with its

recurrence across multiple federal criminal provisions, warrants this Court’s

intervention.

B. 1. The government’s principal merits argument is that this Court already

rejected a similar nondelegation challenge in Touby. BIO 11–13. But Touby

expressly reserved the question presented, and unlike in Touby, the nondelegation

standard is outcome-determinative here.

The Ninth Circuit did not hold that the delegation here would satisfy a

heightened standard; it held only that no heightened standard applies. For good

reason: Unlike in Touby, the delegation here would not pass constitutional muster if

something other than the Ninth Circuit’s interpretation of the “exceedingly modest”

intelligible-principle standard applied. See Pheasant, 129 F.4th at 579. As Keller

explained (Pet. 16), the statute at issue in Touby imposed “multiple specific

restrictions” on the Attorney General’s authority to schedule controlled substances

on an emergency basis. See 500 U.S. at 167. Here, by contrast, Congress provided no

comparable constraints. Sections 821 and 871(b) require no factual findings,

identify no criteria to guide the Attorney General’s exercise of discretion, and

provide no standard for determining where the line between lawful medical practice

and criminal distribution falls. See 21 U.S.C. §§ 821, 871(b).

4

The government attempts to locate constraints elsewhere in the CSA, pointing

to the findings required before the Attorney General may revoke a physician’s

registration, 21 U.S.C. §§ 823(f), 824(a), and the enumerated factors that govern

scheduling a controlled substance, id. §§ 811, 812. BIO 8–9. But neither provision

constrains the delegation at issue here. Sections 823(f) and 824(a) govern a different

power altogether—the decision whether to revoke a practitioner’s registration—not

the standard for distinguishing a lawful prescription from a criminal one. And the

scheduling factors in §§ 811 and 812 constrain only the decision to classify a

substance, not the separate question the Attorney General resolved in § 1306.04(a):

when a registered physician’s dispensing of an already-scheduled substance crosses

from practicing medicine to a federal felony. Indeed, the Ninth Circuit itself did not

rely on §§ 811, 812, 823(f), or 824(a) to sustain the delegation; it looked only to

§§ 821 and 871(b). Pet. App. 19a–21a. Those are the only provisions that delegated

the authority the Attorney General exercised in promulgating § 1306.04(a), and the

government does not identify any meaningful limit to the scope of the delegation.

2. The government’s additional merits arguments fare no better. The

government insists that “it was Congress—not the Attorney General—that made it

a federal crime” to distribute controlled substances “in a manner not ‘authorized by

[the CSA].’” BIO 10. That is true as far as it goes. But it does not go very far.

Congress criminalized the unauthorized distribution of controlled substances.

What Congress did not do—and what the Constitution requires Congress to do—is

define with sufficient specificity what conduct is “authorized” and what conduct is

not. See Pet. 8–15; Sessions v. Dimaya, 584 U.S. 148, 156 (2018). Instead, Congress

5

delegated that definitional task to the Attorney General under the broadest possible

terms: to promulgate regulations “relating to the registration and control of the

manufacture, distribution, and dispensing of controlled substances,” 21 U.S.C.

§ 821, and “which he may deem necessary and appropriate for the efficient

execution of his functions,” 21 U.S.C. § 871(b). The Attorney General, in turn,

issued a regulation stating that a prescription is valid only if issued “for a

legitimate medical purpose” and “in the usual course of professional practice.” 21

C.F.R. § 1306.04(a).

The government suggests (BIO 12–13) that § 1306.04(a)’s standard is rooted in

the CSA. But the handful of somewhat-related phrases the government cobbles

together from disparate contexts—like what counts as a valid prescription for a

mail-order or online pharmacy—does not save the delegation here. The problem is

that Congress delegated unbounded regulatory authority to the Attorney General to

define the elements of a crime; the Attorney General cannot salvage that delegation

by choosing, in his discretion, to track language from entirely unrelated provisions.

See Gonzalez v. Oregon, 546 U.S. 243, 928 n.2 (2006) (Scalia, J., dissenting)

(explaining that the regulation copies a “technically inapplicable statutory

definition contained elsewhere in the statute”). Indeed, the fact the regulation

tracks language Congress later adopted in other statutory provisions only confirms

the delegation problem, as it confirms that Congress can define the scope of

criminal liability with precision when it so chooses. See BIO 12–13. It did not do so

here.

6

The government’s reliance on Moore is equally misplaced. BIO 10. Moore did not

address—much less resolve—a nondelegation challenge. And Moore never identifies

where in the text of the CSA the § 1306.04(a) standard is found. See 423 U.S. at

137–43 & n.13. Moore therefore provides no support for the government’s position

that the delegation here is constitutional. To the extent Moore bears on this case at

all, it confirms only that the regulatory standard has been in place for decades—not

that it rests on a constitutionally adequate delegation.

The government’s analogies to prior delegations that have passed constitutional

muster illustrate just how unconstrained the delegation is here. See BIO 10–12. For

example, it analogizes to 8 U.S.C. § 1325(a)(1), which makes it a crime to enter the

United States “at any time or place other than as designated by immigration

officers.” BIO 11. But the designation of ports of entry is a ministerial act. The

criminal prohibition is for entering elsewhere, and Congress defined the actus reus

of the crime. Even Grimaud, a case decided before the modern nondelegation

doctrine developed, involved a regulatory prohibition on unlicensed sheep grazing

that arose from a statute that offered far more guidance than the CSA. See 220 U.S.

at 509 (noting that Congress directed the Secretary of Agriculture to “regulat[e] the

use and occupancy of the public forest reservations and preserv[e] the forests

thereon from destruction”).

The government’s reliance on Loving, fares no better. BIO 10–11, 13–14. Loving

involved a delegation to the President in his capacity as Commander in Chief to

prescribe aggravating factors for courts-martial in capital cases. See 517 U.S. at

751. The Court upheld that delegation in part because of the unique constitutional

7

authority vested in the President over military justice and in part because Congress

had already defined the offense (premeditated murder) and fixed the range of

punishment (including death). Id. at 753–54, 768–73. The President’s role was thus

limited to specifying the circumstances under which the maximum penalty could be

imposed within that congressionally established range. Id. at 768–69, 772–73.

Here, there is no comparable constitutional warrant for deference, and Congress

did not define the offense with comparable precision. The Attorney General did not

merely specify aggravating factors within a framework Congress supplied; the

Attorney General supplied the framework itself. And none of these cases addressed

the question this Court reserved in Touby: whether something more than an

intelligible principle is required when Congress delegates the power to define

criminal conduct.

C. This case is an ideal vehicle for resolving the question presented. As the

government acknowledges (BIO 4–5), Keller consistently argued below that his 21

U.S.C. § 841 convictions violated the nondelegation doctrine because the Attorney

General, through § 1306.04(a), fixed the substantive standard dividing lawful

medical practice from criminal distribution. And the Ninth Circuit rejected that

challenge on the merits, holding that Keller’s argument for “something greater than

an intelligible principle” was foreclosed by Pheasant. The court made no alternative

holding that the delegation would survive a heightened standard. Pet. App. 16a–

22a. Notwithstanding that clean presentation, the government raises two vehicle

objections. BIO 15–16. Neither withstands scrutiny.

8

1. First, the government now contends that Keller’s conviction was not in fact

based on § 1306.04(a)’s substantive standard because the indictment and jury

instruction did not cite the regulation. BIO 15–16. The government did not advance

this position below, and it is demonstrably wrong: The government could not have

convicted Keller without relying on § 1306.04(a), as his conduct would have

otherwise been lawful under the statute.

As the Court recognized in Ruan, the operative prescription standard comes

only from § 1306.04(a), not the text of § 841(a) itself or any other provision. See

Ruan v. United States, 597 U.S. 450, 454, 455 (2022). For that reason, the substance

of each § 841 count charged in the indictment precisely mirrored the language of

§ 1306.04(a), alleging that Keller was criminally liable because his distribution of

controlled substances was “outside the scope of professional practice and not for a

legitimate medical purpose.” See D. Ct. Doc. 132, at 1–5 (Aug. 26, 2021). The Ninth

Circuit recognized that § 1306.04 formed the basis of Keller’s criminal liability,

explaining that Keller “was subject to the penalties of the CSA . . . because of his

failure to comply with § 1306.04(a) . . . a regulation promulgated by the executive

branch pursuant to 21 U.S.C. §§ 821 and 871(b).” Pet. App. 19a.

That the jury instructions did not separately cite the regulation is also

unremarkable, as jurors are routinely instructed on the substance of the applicable

legal standard without being told its precise statutory or regulatory source. See, e.g.,

Bass v. United States, 324 F.2d 168, 171 (8th Cir. 1963) (Blackmun, J.). As the

Ninth Circuit recognized, Keller’s liability rested on the regulatory standard, and

the panel therefore evaluated the delegation under the intelligible-principle test.

9

Pet. App. 19a, 21a–22a. This Court should reject the government’s post hoc

suggestion that the regulation was somehow incidental to convictions obtained

under the regulation’s operative words.

2. Second, the government raises a severability concern: It maintains that if

Keller prevails, the proper remedy would be to sever § 841(a)’s exception allowing

authorized uses of controlled substances altogether. BIO 16. That argument

misunderstands both the statutory scheme and the judgment below.

Keller’s challenge is limited to whether Congress properly delegated the

Attorney General rulemaking authority under 21 U.S.C. §§ 821 and 871(b). Section

1306.04(a) is an exercise of that rulemaking authority, and it expands the CSA by

making a registered physician criminally liable when he issues a prescription

lacking a “legitimate medical purpose.” See 21 C.F.R. § 1306.04(a). This Court can

provide full relief to Keller by invalidating § 1306.04(a) as an exercise of improperly

delegated authority under §§ 821 and 871(b).

That relief would not disturb the CSA’s exception for licensed physicians, as

that exception does not depend on the Attorney General’s rulemaking authority. In

particular, § 841(a) prohibits distributing or dispensing drugs “[e]xcept as

authorized” by the CSA. 21 U.S.C. § 841(a). Section 822(b), in turn, authorizes

registered persons, including licensed physicians like Keller, to dispense controlled

substances “to the extent authorized by their registration and in conformity with

the other provisions” of the CSA. 21 U.S.C. § 822(b). Thus, the CSA itself exempts

registered physicians from § 841’s purview, and the statute would continue to do so

10

even if this Court curbed the Attorney General’s unbounded regulatory authority

under §§ 821 and 871(b).

The government’s severability argument, meanwhile, strains credulity. This

Court will not presume that Congress “intended a constitutionally flawed provision

to be severed from the remainder of the statute if the balance of the legislation is

incapable of functioning independently.” Alaska Airlines, Inc. v. Brock, 480 U.S.

678, 684 (1987); see also Barr v. American Association of Political Consultants, 591

U.S. 610, 628 (2020) (opinion of Kavanaugh, J.). That is the case here: Section

841(a)’s authorized-use exception has existed since the statute’s enactment and is

essential to its design. Simply put, Congress could not have intended to create a

statute that would make every prescribing doctor—from oncologists to

psychiatrists—a felon, and the government cannot seriously push a severability

argument that would lead to that result.

II. Alternatively, the Court should hold this petition pending disposition

of Pheasant v. United States, No. 25-6911.

If the Court does not grant plenary review in this case, it should instead hold

this petition pending resolution of the petition in Pheasant v. United States, No. 256911, which seeks review of the decision the court of appeals relied on to reject

Keller’s nondelegation argument below. See Pet. 18–19; Pet. App. 22a. The

government does not dispute that the Court should hold this petition if the Court

grants certiorari in that case. See BIO 7, 13–14. If the Court does so and resolves

the question favorably to the petitioner there, or otherwise abrogates the standard

11

the Ninth Circuit applied below, the Court should then grant this petition, vacate

the judgment, and remand for further proceedings consistent with that decision.

CONCLUSION

The petition should be granted.

Respectfully submitted,

August 13, 2026

JODI LINKER

Federal Public Defender

Northern District of California

TODD M. BORDEN*

Assistant Federal Public Defender

* Counsel of Record for Petitioner

12