Amicus Curiae Brief — Suncor Energy (U.S.A.) Inc., et al., Petitioners v. County Commissioners of Boulder County, et al.

No. 25-170

In the Supreme Court of the United States

SUNCOR ENERGY (U.S.A.) INC., ET AL.,

Petitioners,

v.

COUNTY COMMISSIONERS OF BOULDER COUNTY, ET AL.

On Writ of Certiorari to

the Supreme Court of Colorado

BRIEF OF AMICUS CURIAE

NEUTRAL PRINCIPLES

SUPPORTING PETITIONERS AND REVERSAL

ERIK S. JAFFE

SCHAERR | JAFFE LLP

1717 K Street NW

Suite 900

Washington, DC 20006

Telephone: (202) 787-1060

ejaffe@schaerr-jaffe.com

EUGENE VOLOKH

Counsel of Record

SCHAERR | JAFFE LLP

One Embarcadero Center

Suite 1200

San Francisco, CA 94111

Telephone: (415) 562-4942

evolokh@schaerr-jaffe.com

Counsel for Amicus Curiae

MAY 21, 2026

QUESTIONS PRESENTED

1. Whether federal law precludes state-law

claims seeking relief for injuries allegedly caused by

the effects of interstate and international greenhousegas emissions on the global climate.

2. Whether this Court has statutory and Article

III jurisdiction to hear this case.

ii

TABLE OF CONTENTS

QUESTIONS PRESENTED......................................... i

TABLE OF AUTHORITIES ....................................... iv

INTEREST OF AMICUS CURIAE............................. 1

SUMMARY OF ARGUMENT ..................................... 2

ARGUMENT ................................................................ 3

I.

The First Amendment Protects

Advocacy, Petitioning, and Expressive

Association Related to Debates About

Climate Change. ............................................. 3

A.

Climate-Change Lawsuit Claims

Rest in Part on Defendants’

Constitutionally Protected Speech,

Petitioning, and Association. .................. 5

B.

The First Amendment Protects

Speech on Scientific Questions. ............ 10

C.

The First Amendment Protects

Speech on Scientific Questions

Touching on One’s Business. ................ 13

D.

The First Amendment Protects

Petitioning the Government. ................ 17

E.

The First Amendment Protects

Expressive Association.......................... 19

F.

The First Amendment Protects the

Right Not to Speak ................................ 21

II.

iii

Imposing Liability for Interstate and

International Activity Based on the

Local Downstream Consequences of

Such Extraterritorial Behavior Is

Beyond the Power of Individual States

Under the Foreign Commerce Clause.......... 24

CONCLUSION .......................................................... 32

iv

TABLE OF AUTHORITIES

Cases

Page(s)

303 Creative LLC v. Elenis,

600 U.S. 570 (2023) ................................................ 22

Allied Tube & Conduit Corp. v.

Indian Head, Inc., 486 U.S. 492 (1988)................. 15

Americans for Prosperity Found. v. Bonta,

594 U.S. 595 (2021) ................................................ 21

Atlantic Cleaners & Dyers v. United States,

286 U.S. 427 (1932) ................................................ 29

Bolger v. Youngs Drug Prods. Corp.,

463 U.S. 60 (1983) .................................................. 14

California Motor Transp. Co. v.

Trucking Unltd., 404 U.S. 508 (1972) ................... 18

Central Hudson Gas & Elec. Corp. v.

Public Serv. Comm’n, 447 U.S. 557 (1980) ........... 14

Chiles v. Salazar,

146 S. Ct. 1010 (2026) ............................................ 12

Consolidated Edison Co. v. Public Serv.

Comm’n of N.Y., Inc., 447 U.S. 530 (1980) ...... 14, 15

Crutcher v. Kentucky,

141 U.S. 47 (1891) .................................................. 29

Eastern R.R. Presidents Conf. v. Noerr Motor

Freight, Inc., 365 U.S. 127 (1961) ..................... 4, 18

First Choice Women’s Res. Ctrs., Inc.

v. Davenport, 146 S. Ct. 1114 (2026) ............... 20, 21

v

First Nat’l Bank of Boston v. Bellotti,

435 U.S. 765 (1978) ................................................ 15

FTC v. Superior Ct. Trial Lawyers Ass’n,

493 U.S. 411 (1990) .................................................. 4

Gibbons v. Ogden,

22 U.S. (9 Wheat.) 1 (1824).................................... 27

Gonzales v. Raich,

545 U.S. 1 (2005) .................................................... 31

Harris v. Huntington,

2 Tyl. 129 (Vt. 1802)................................................. 4

Hustler Mag., Inc. v. Falwell,

485 U.S. 46 (1988) .................................................... 4

Janus v. American Fed’n of State, Cnty.

& Mun. Emps., 585 U.S. 878 (2018)...................... 22

Japan Line, Ltd. v. Los Angeles County,

441 U.S. 434 (1979) ................................................ 30

Martin v. Hunter’s Lessee,

14 U.S. (1 Wheat.) 304 (1816).......................... 25, 26

Miami Herald Publ’g Co. v. Tornillo,

418 U.S. 241 (1974) ................................................ 22

Miller v. California,

413 U.S. 15 (1973) .................................................. 11

NAACP v. Alabama ex rel.

Patterson, 357 U.S. 449 (1958) ........................ 20, 21

NAACP v. Claiborne Hardware Co.,

458 U.S. 886 (1982) ...................................... 4, 20, 21

National Inst. Fam. & Life Advocs. v. Becerra,

585 U.S. 755 (2018) ................................................ 23

vi

Nike, Inc. v. Kasky,

539 U.S. 654 (2003) .......................................... 16, 17

Northwestern States Portland Cement Co.

v. Minnesota, 358 U.S. 450 (1959) ......................... 30

Pacific Gas & Elec. Co. v. Public Utils.

Comm’n of Cal., 475 U.S. 1 (1986) ....................... 22

Professional Real Estate Invs., Inc.

v. Columbia Pictures Indus., Inc.,

508 U.S. 49 (1993) .................................................. 19

R.A.V. v. City of St. Paul,

505 U.S. 377 (1992) ................................................ 16

Reid v. Delorme,

4 S.C.L. (2 Brev.) 76

(S.C. Const. Ct. App. 1806) ...................................... 4

Riley v. National Fed’n of Blind of N.C., Inc.,

487 U.S. 781 (1988) ................................................ 23

Roman Cath. Diocese of Brooklyn v. Cuomo,

592 U.S. 14 (2020) .................................................. 12

Roth v. United States,

354 U.S. 476 (1957) ................................................ 17

Runkle v. Meyer,

3 Yeates 518 (Pa. 1803) ........................................... 4

Smith v. Turner,

48 U.S. (7 How.) 283 (1849) ............................. 27, 28

Southern Pac. Co. v. Arizona ex rel. Sullivan,

325 U.S. 761 (1945) .......................................... 29, 30

United Mine Workers of Am. v. Pennington,

381 U.S. 657 (1965) ............................................ 4, 15

vii

United States v. Alvarez,

567 U.S. 709 (2012) .......................................... 10, 11

United States v. Lopez,

514 U.S. 549 (1995) ................................................ 31

United States v. Skrmetti,

605 U.S. 495 (2025) .......................................... 12, 13

Zauderer v. Office of Disciplinary

Counsel, 471 U.S. 626 (1985) ........................... 14, 23

Constitutional Provisions

U.S. Const. amend. X ................................................ 26

U.S. Const. art. I .................................................. 25, 28

Cal. Const. art. I, § 16 ............................................... 12

Mont. Const. art. II, § 26 ........................................... 12

Rule

Fed. R. Civ. P. 48 ....................................................... 12

Treatise

Joseph Story,

Commentaries on the Constitution of the

United States (Bos., Hilliard, Gray & Co.

1833) ....................................................................... 28

Other Authorities

1st Req. Prod. of Docs.,

City & County of Honolulu v.

Sunoco LP, No. 1CCV-20-0000380 (LWC)

(Haw. Cir. Ct., 1st Cir. Aug. 26, 2024) .................. 19

viii

2d Am. Complaint,

Connecticut v. Exxon Mobil Corp.,

No. HHD-CV20-6132568-S

(Conn. Super. Ct., Hartford Cnty.

Nov. 8, 2024) .......................................................... 22

Albert S. Abel,

The Commerce Clause in the Constitutional

Convention and in Contemporary Comment,

25 Minn. L. Rev. 432 (1941) .................................. 31

Complaint,

City of Imperial Beach v. Chevron Corp.,

No. C17-01227 (Cal. Super. Ct.,

Contra Costa Cnty. July 17, 2017) .......................... 9

Complaint,

City of Richmond v. Chevron Corp.,

No. C18-00055 (Cal. Super. Ct.,

Contra Costa Cnty. Jan. 22, 2018) .......................... 9

Complaint,

Leon v. Exxon, No. 25-2-15986-8-SEA

(Wash. Super. Ct., King Cnty. May 29, 2025) ...... 22

Complaint,

Minnesota v. American Petroleum Inst.,

No. 62-CV-20-3837 (Minn. Dist. Ct.,

Ramsey Cnty. June 24, 2020) ................................ 22

Const. Diary (Phila.), Dec. 14, 1799 ............................ 4

Paula Hannaford-Agor & Morgan Moffett,

2023 State-of-the-States Survey of

Jury Improvement Efforts: Civil Jury

Trials, Nat’l Ctr. for State Cts. (2025) .................. 13

ix

Letter from Stephanie D. Biehl,

Sher Edling, LLP & Dana M.O. Viola,

Corporation Counsel, to Jerry M. Hiatt,

Hiatt & Hiatt, in the matter of

City & County of Honolulu v. Sunoco, LP,

Case No. 1ccv-20-0000380 (Haw. Cir. Ct.,

1st Cir. Apr. 10, 2026).............................................. 7

Pl. Multnomah County’s Resp. to Mot.

to Dismiss, County of Multnomah v.

Exxon Mobil Corp., No. 23-cv-25164

(Ore. Cir. Ct., Multnomah Cnty.

July 8, 2025) ............................................................. 8

Pl.’s 1st Reqs. Prod. of Docs.,

Vermont v. Exxon Mobil Corp.,

No. 21-CV-02778 (Vt. Super. Ct.

Oct. 13, 2025) ......................................................... 20

Pls.’ 1st Req. Prod. of Docs.,

City of Annapolis v. BP P.L.C.,

No. C-02-CV-21-000250 (Md. Cir. Ct.,

Anne Arundel Cnty. Aug. 13, 2024) ...................... 20

Pls.’ Mot. to Remand,

County of Multnomah v. Exxon Mobil Corp.,

No. 3:23-cv-1213-YY, 2024 WL 2938473

(D. Or. June 10, 2024), ECF No. 98 .................... 8, 9

Eugene Volokh,

Tort Liability and the Original Meaning of

the Freedom of Speech, Press, and Petition,

96 Iowa L. Rev. 249 (2010) ...................................... 4

INTEREST OF AMICUS CURIAE 1

Amicus Neutral Principles is a nonprofit, nonpartisan organization created to promote the consistent

and rigorous application of neutral legal principles

emphasizing fidelity to the text and structure of the

Constitution and laws regardless of outcome. Its mission is to apply traditionally conservative legal methods in a rigorously nonpartisan way—ensuring that

both substantive and procedural constitutional safeguards against government overreach are upheld, regardless of shifting political winds. As jurists and

scholars such as Judge Bork, Professor Wechsler, and

many others before and since have recognized, the unprincipled exercise of judicial power in pursuit of particular results is unsustainable and illegitimate. Since

the 1980s, conservative scholarship and jurisprudence

have demonstrated that such neutral principles are

best found in a faithful, unbiased adherence to the

original public meaning of the text of the Constitution,

and, when necessary, relevant history and tradition

that may help resolve any ambiguities in that text.

Neutral Principles is interested in this case because it involves attempts to impose liability for core

political speech and public debate over scientific and

economic issues as a means of punishing disfavored

speakers and ideas. Such punishments abridge the

core meaning and function of the First Amendment’s

protections for speech, association, and petitioning the

1 This brief was not authored in whole or in part by counsel for

any party and no person or entity other than amicus curiae, its

members, or its counsel has made a monetary contribution toward the brief’s preparation or submission.

2

government. The First Amendment violations highlighted by plaintiffs’ newfound emphasis on speechbased claims provide an additional reason to treat lawsuits over such national and global issues as preempted or barred by federal law and the Constitution

in order to avoid the profound First Amendment burdens that would arise if this suit is allowed to proceed.

They also provide independent alternative grounds to

reverse the judgment below.

This case also involves an attempt by territorially

limited government entities to regulate national and

international speech and commerce based on the

claimed downstream consequences of decisions made

by millions of subsequent actors. Extraterritorial overreach by state or local governments is contrary to the

original meaning of the Commerce Clause and other

structural components of the Constitution constraining such overreach.

SUMMARY OF ARGUMENT

Trying to avoid federal preemption, plaintiffs in

this and other climate-change cases have shifted from

claims targeting emissions to claims alleging supposed

“deception.” These “deception”-based claims are still

preempted, because they still target emissions by

seeking relief for injuries allegedly caused by emissions. But that shift also threatens numerous First

Amendment violations and the possibility of conflicting regulations of national speech, association, and petitioning that further support preemption of such local

efforts. Climate-change plaintiffs seek to punish energy companies not just for the asserted consequences

of emissions, which result from the decisions and

3

actions of millions of other actors and governments,

but for the companies’ speech about climate change

that plaintiffs claim led to such emissions.

This case is an example of this pattern, but it is

not an outlier: There are many like it across the country. And there likely will be many more in the field of

climate change, with some potentially taking diametrically opposed views of what scientific speech is true

or false. This Court should keep the serious First

Amendment issues underlying this litigation campaign in mind in deciding this case. The danger to

First Amendment rights is another reason favoring

uniform national regulation of these issues as opposed

to opportunistic state and local overreach that seeks to

punish and suppress speech and debate on this controversial topic.

ARGUMENT

I.

The First Amendment Protects Advocacy,

Petitioning, and Expressive Association Related to Debates About Climate Change.

The speech that forms the basis for alleged liability in this case is core advocacy, petitioning, and expressive association that is protected by the First

Amendment. Merely characterizing it as “marketing”

does nothing to change its essential nature and its constitutional protection.

Attempts to impose liability based in part on constitutionally protected speech are subject to First

Amendment scrutiny (and, as Parts I.B-F show, fail

such scrutiny). Since the Framing Era, American law

has recognized that civil liability claims based on expression are subject to constitutional scrutiny.

4

Before the Fourteenth Amendment and the subsequent incorporation of the First Amendment, this

took place under state constitutional free expression

provisions. Many early cases from 1799 on acknowledge that civil lawsuits are subject to state constitutional provisions protecting the right to petition,

speak, and print. Eugene Volokh, Tort Liability and

the Original Meaning of the Freedom of Speech, Press,

and Petition, 96 Iowa L. Rev. 249, 253-254 (2010); see,

e.g., Harris v. Huntington, 2 Tyl. 129, 145-146 (Vt.

1802) (rejecting tort liability based partly on the constitutional right to petition); Reid v. Delorme, 4 S.C.L.

(2 Brev.) 76, 79 (S.C. Const. Ct. App. 1806) (likewise);

see also, e.g., Const. Diary (Phila.), Dec. 14, 1799, at 3

(article on Rush v. Cobbett) (reporting on a jury instruction that recognized that the free press provision

of the state constitution applied to tort liability);

Runkle v. Meyer, 3 Yeates 518, 520 (Pa. 1803) (likewise).

Following in this tradition, and after the incorporation of the First Amendment, civil lawsuits based on

speech have been constrained by the First Amendment. See, e.g., NAACP v. Claiborne Hardware Co.,

458 U.S. 886 (1982); Hustler Mag., Inc. v. Falwell, 485

U.S. 46 (1988). This Court’s Noerr/Pennington line of

cases regarding antitrust liability took the same approach, interpreting federal statutes “in the light of

the First Amendment[].” FTC v. Superior Ct. Trial

Lawyers Ass’n, 493 U.S. 411, 424 (1990); see, e.g., Eastern R.R. Presidents Conf. v. Noerr Motor Freight, Inc.,

365 U.S. 127 (1961); United Mine Workers of Am. v.

Pennington, 381 U.S. 657 (1965).

5

The decisions cited above applied the First

Amendment even where the plaintiffs were private entities, recognizing that the plaintiffs’ invocation of the

government’s coercive power through the courts sufficed to trigger constitutional scrutiny. Here, where

plaintiffs are themselves government entities, constitutional constraints are doubly applicable.

A.

Climate-Change Lawsuit Claims Rest in

Part on Defendants’ Constitutionally

Protected Speech, Petitioning, and Association.

There is no genuine doubt that the recent climatechange lawsuits brought by governments turn on defendants’ political advocacy. Notwithstanding the assertion by plaintiffs that they “do not seek to impose

liability” based on defendants’ “speech,” “participat[ion] in public debates,” or “lobbying or petitioning.”

J.A.139, ¶¶ 541-542, that is precisely what they are

doing. Plaintiffs expressly “seek to impose liability on

Defendants in connection with misrepresentations

about the known dangers of their products, in connection with their marketing of those products and in connection with the sale of those products,” J.A.139,

¶ 541. But they include all public speech directly or indirectly related to their products and climate change

under the rubric of “marketing” and have a boundless

conception of what speech is “in connection” with marketing and sales, making their disclaimer meaningless. Other parts of the Amended Complaint show that

these supposed misrepresentations do indeed include

“participat[ion] in public debates” about climate

change.

6

In Part III.C of their Amended Complaint, titled

“Defendants’ fossil fuel activities have caused and will

continue to cause Plaintiffs’ damages and losses,”

J.A.84, Plaintiffs fault Defendants for supposedly

“act[ing] to thwart public awareness and understanding through misleading advertising and other communications.” J.A.106, ¶ 418. They claim Defendants “ran

multiple advertisements downplaying the risks of climate change and emphasizing uncertainty.” J.A.107,

¶ 419. They similarly claim defendants “criticized” the

“Kyoto process,” and “emphasized scientific uncertainties.” J.A.107, ¶ 421 (cleaned up).

They likewise attack the defendants’ expressive

associations, arguing that defendants “communicated

through API [the American Petroleum Institute], and

groups that were created, organized or controlled by

API,” such as “the Global Climate Coalition,” which

“spent millions of dollars on advertising that tried to

discredit climate science, and cast doubt on the dangerous consequences of climate change.” J.A.107-108,

¶¶ 422-424. They further allege that, through another

organization, defendants aimed “to get a majority of

the American public to recognize that significant uncertainties exist in climate science and to make climate change a non-issue, meaning that the Kyoto Protocol is defeated and there are no further initiatives to

thwart the threat of climate change.” J.A.108-109,

¶ 427 (cleaned up). And they claim that defendants

“promoted the work” of “a cadre of claimed climate scientists” “to cast doubt on climate science.” J.A.109,

¶¶ 429-430. See generally J.A.104-112, ¶¶ 407-443 (offering many more examples of such speech, and of its

persuasiveness to the public). Whatever one might

7

think of the merits of such speech, it was indeed

speech, participation in political debate, lobbying, and

petitioning (as well as expressive association). Such

examples are core First Amendment activity, not

merely the sort of product advertising so directly part

of specific commercial transactions that it would be

categorized as commercial speech (see Part I.C infra).

In a similar case brought by Honolulu, plaintiffs

sought to depose hundreds of third-party witnesses,

including alleged “climate-denial leaders and authors

of climate disinformation, PR strategists, and fringe

scientists and academics,” “Hawaiʻi and national media organizations,” “think tanks,” and “interest groups

related to Defendants’ misinformation campaign.” Letter from Stephanie D. Biehl, Sher Edling, LLP & Dana

M.O. Viola, Corporation Counsel, to Jerry M. Hiatt,

Hiatt & Hiatt, in the matter of City & County of Honolulu v. Sunoco, LP, Case No. 1ccv-20-0000380 (Haw.

Cir. Ct., 1st Cir. Apr. 10, 2026), available at https://

perma.cc/8JJY-B5J9. That too illustrates how climatechange lawsuit plaintiffs are broadly targeting public

commentary on scientific and political matters, as well

as the expressive associations that engage in such debates.

Other climate-change lawsuits likewise routinely

target defendants’ public statements as part of the basis for supposed liability. The Introduction to a recent

Multnomah County brief makes this clear: The opening sentence reads,

For decades, powerful corporations have engaged in the same pattern of undermining

the

scientific

consensus,

suppressing

8

unfavorable research, and manufacturing

uncertainty through misinformation campaigns on issues critical to public safety—issues like tobacco, asbestos, opioids, obesity

and climate change—all for financial gain.

Pl. Multnomah County’s Resp. to Mot. to Dismiss at 1,

County of Multnomah v. Exxon Mobil Corp., No. 23-cv25164 (Ore. Cir. Ct., Multnomah Cnty. July 8, 2025).

Later on the same page, the brief asserts that “Defendants continue to glorify fossil fuels, arguing that any

downside to their consumption is simply outweighed

by their utility, without addressing Defendants’ deeprooted public deception or its disastrous consequences

in Oregon upon which Plaintiff’s claims are based.”

Ibid. It argues that defendants seek “to quell concerns

and thoroughly confuse the public about the dangers

of greenhouse gasses and the seriousness of anthropogenic climate change, thus impeding actions to prepare for the consequences of climate change.” Ibid.

Climate-change lawsuit plaintiffs likewise target

speech when they argue that defendants are engaged

in a “misinformation campaign” “to downplay and/or

outright deny the causal relationship between their

GHG emissions and extreme weather events.” Pls.’

Mot. to Remand at 9, 10, County of Multnomah v.

Exxon Mobil Corp., No. 3:23-cv-1213-YY, 2024 WL

2938473 (D. Or. June 10, 2024), ECF No. 98. Indeed,

they assert that this has been done “through both legitimate and illegitimate means.” Ibid. While the

meaning of “illegitimate means” here is not clear, the

statement acknowledges that much of the means were

not otherwise criminal or tortious. And much of the

means consisted of fully First-Amendment-protected

9

activity—whether public advocacy, lobbying, or legal

challenges to government action—and not mere commercial advertising, e.g.:

Space Age filed a lawsuit in September 2020

in Oregon Circuit Court against then-Oregon

governor Kate Brown alleging that Governor

Brown’s executive order directing state agencies to reduce greenhouse gas emissions violated separation of powers principles in the

Oregon Constitution. Space Age has been an

active participant in downplaying the need to

reduce GHG emissions * * *.

Id. at 10 (footnote and citation omitted).

Similarly, in their arguments about personal jurisdiction over fossil-fuel companies, various plaintiffs

often identify the allegedly tortious behavior as including political advocacy. One lawsuit, for instance,

stresses defendants’ “efforts to influence statutory and

regulatory debate regarding fossil fuel consumption,

electric power distribution, and greenhouse gas pollution policies,” including “lobbying expenditures directed at numerous statutory and regulatory proposals.” Complaint ¶ 29(e), City of Imperial Beach v.

Chevron Corp., No. C17-01227 (Cal. Super. Ct., Contra

Costa Cnty. July 17, 2017); see also Complaint ¶ 32(e),

City of Richmond v. Chevron Corp., No. C18-00055

(Cal. Super. Ct., Contra Costa Cnty. Jan. 22, 2018).

Plaintiffs similarly aim to hold many companies liable

for their association with industry groups that seek to

promote political messages. See infra Part I.E.

10

B.

The First Amendment Protects Speech

on Scientific Questions.

The speech over which climate change plaintiffs

routinely sue is fully protected by the First Amendment, because it is advocacy on matters of core public

concern and public policy.

In United States v. Alvarez, five members of this

Court expressly recognized that the government cannot try to “penalize purportedly false speech” on such

matters. 567 U.S. 709, 731 (2012) (Breyer, J., concurring in judgment). Justice Alito, joined by Justices

Scalia and Thomas, reasoned:

[T]here are broad areas in which any attempt

by the state to penalize purportedly false

speech would present a grave and unacceptable danger of suppressing truthful speech.

Laws restricting false statements about philosophy, religion, history, the social sciences,

the arts, and other matters of public concern

would present such a threat. The point is not

that there is no such thing as truth or falsity

in these areas or that the truth is always impossible to ascertain, but rather that it is perilous to permit the state to be the arbiter of

truth.

Id. at 751-752 (Alito, J., dissenting). Justice Breyer,

joined by Justice Kagan, expressly echoed this:

As the dissent points out, “there are broad areas in which any attempt by the state to penalize purportedly false speech would present a grave and unacceptable danger of suppressing truthful speech.” Laws restricting

11

false statements about philosophy, religion,

history, the social sciences, the arts, and the

like raise such concerns, and in many contexts have called for strict scrutiny.

Id. at 731-732 (Breyer, J., concurring in the judgment).

Justice Kennedy’s plurality opinion did not discuss

this point, but that was likely because the plurality

took an even more speech-protective view than did the

concurrence and the dissent, see id. at 726-729, and

thus saw no need for focusing specially on these categories of speech.

These opinions specifically refer to “the social sciences,” but their logic applies equally to other sciences.

There too “it is perilous to permit the state to be the

arbiter of truth.” There too placing public debate at the

mercy of federal, state, and county officials, as well as

of judges and jurors, “would present a grave and unacceptable danger of suppressing truthful speech.” There

too the underlying speech is on matters of the most serious “public concern.”

Indeed, this Court has long spoken of broad protection for “scientific expression”: “[I]n the area of freedom of speech and press the courts must always remain sensitive to any infringement on genuinely serious literary, artistic, political, or scientific expression.”

Miller v. California, 413 U.S. 15, 22-23 (1973). And

that is especially apt in the climate change cases,

where the “scientific expression” is intimately tied

with “political * * * expression” on difficult public policy questions—such as whether the “downside to [the]

consumption [of fossil fuels] is simply outweighed by

their utility,” see supra p. 8.

12

As this Court has recognized in recent years,

many questions yield “fierce scientific and policy debates.” United States v. Skrmetti, 605 U.S. 495, 525

(2025). See, e.g., Chiles v. Salazar, 146 S. Ct. 1010,

1027-1029 (2026) (discussing both the modern debate

about sexual orientation and gender identity conversion therapy, and the past debate about whether homosexuality was a “mental disorder”); Skrmetti, 605

U.S. at 500-505, 523-525 (discussing the debate over

youth gender medicine); Roman Cath. Diocese of

Brooklyn v. Cuomo, 592 U.S. 14 (2020) (per curiam)

(resolving the Free Exercise Clause question against

the backdrop of the debate over COVID-19 lockdowns).

Human nature being what it is, the “fierce[ness]” of

the debates may manifest through each side feeling so

strongly about its own correctness that it does not believe that there is indeed a genuine debate.

Partisans may be confident that the science is settled in their favor, and that only liars would contest

that conclusion. Jurors may take the same view. Especially in relatively ideologically homogeneous communities, such jurors may well form the required supermajority for imposing massive liability on those with

whom they disagree. In federal courts, civil juries

must at least be unanimous. Fed. R. Civ. P. 48. But

most state court systems do not require civil jury unanimity. See, e.g., Mont. Const. art. II, § 26 (providing

for a verdict by a 2/3 vote); Cal. Const. art. I, § 16

(providing for a verdict by a 3/4 vote); Paula Hannaford-Agor & Morgan Moffett, 2023 State-of-the-States

Survey of Jury Improvement Efforts: Civil Jury

13

Trials 5 & fig. 3, Nat’l Ctr. for State Cts. (2025),

https://tinyurl.com/5mn4nrzj (cataloging the rules in

all states).

Yet the supposed “expert consensus” relied on by

decision makers—county officials, judges, jurors, and

others—is often illusory. And in any event, that consensus cannot be a substitute for the ongoing process

of free discussion that the First Amendment prescribes.

“[T]he American people and their representatives

are entitled to disagree with those who hold themselves out as experts” in enacting legislation. Skrmetti,

605 U.S. at 530 (Thomas, J., concurring). And they are

likewise entitled to hear from those who disagree with

the putative experts. Resolving the policy implications

of scientific debates is left “to the people, their elected

representatives, and the democratic process.” Id. at

525 (majority op.). Challenging the conventional wisdom of the day is often the foundation of political, social, and scientific advances. Indeed, such freedom of

speech on all questions, including scientific ones, is

what allows “the democratic process” to function.

C.

The First Amendment Protects Speech

on Scientific Questions Touching on

One’s Business.

Just as the First Amendment protects the right of

fossil fuel critics to speak about scientific matters, it

protects the same right of fossil fuel defenders, including fossil fuel producers. Whatever the justifications

and merits of less rigorous protection for commercial

advertising under this Court’s jurisprudence, e.g., Bolger v. Youngs Drug Prods. Corp., 463 U.S. 60, 65-68

14

(1983), this Court tolerates such differential treatment

precisely because “[a] company has the full panoply of

protections available to its direct comments on public

issues.” Id. at 68.

In Zauderer v. Office of Disciplinary Counsel, this

Court concluded that speech about medical matters in

a lawyer’s commercial advertising was less protected

commercial speech in part because “Ohio has placed

no general restrictions on appellant’s right to publish

facts or express opinions regarding Dalkon Shield litigation; Ohio’s Disciplinary Rules prevent him only

from conveying those facts and opinions in the form of

advertisements of his services as an attorney.” 471

U.S. 626, 637 n.7 (1985) (quoting the “full panoply of

protections available to its direct comments on public

issues” statement from Bolger, 463 U.S. at 68). Central

Hudson Gas & Electric Corp. v. Public Service Commission likewise distinguished commercial speech

from fully protected “direct comments on public issues” by energy companies. 447 U.S. 557, 562 n.5

(1980). Whatever this Court may eventually decide as

to reduced protection for commercial speech, any such

reduction necessarily depends on businesses retaining

the freedom to speak in public debate, even if not in

purely commercial advertising.

Indeed, the case that Bolger cited for the “full panoply of protections” proposition—Consolidated Edison

Co. v. Public Service Commission of New York, Inc.,

447 U.S. 530 (1980)—involved an energy company promoting an environmentally controversial energy

source (in that case, nuclear power). See Bolger, 463

U.S. at 68 n.16. And this Court in Consolidated Edison

15

treated such speech as fully protected “participat[ion]

in * * * public debate.” 447 U.S. at 535.

Furthermore, this Court has long recognized that

a company’s motivation to protect its own business

through its speech does not strip the speech of full protection. “Noerr shields from the Sherman Act a concerted effort to influence public officials regardless of

intent or purpose.” Pennington, 381 U.S. at 670.

And while private collusion may be regulated under the antitrust laws, that is so precisely because

public speech remains fully protected: Even businesses who seek anticompetitive legislation “can, with full

antitrust immunity, engage in concerted efforts to influence * * * governments through direct lobbying,

publicity campaigns, and other traditional avenues of

political expression.” Allied Tube & Conduit Corp. v.

Indian Head, Inc., 486 U.S. 492, 510 (1988). Likewise,

businesses can “present[] and vigorously argu[e] accurate scientific evidence before a nonpartisan private

standard-setting body.” Id. Businesses can surely do

the same before the public more generally.

Speech on public issues, even by companies with

an economic interest in the outcome, is protected in

large part because speech can be valuable to listeners

regardless of the speaker’s identity. Corporate

speech—which will usually be economically self-interested—is protected “based not only on the role of the

First Amendment in fostering individual self-expression but also on its role in affording the public access

to discussion, debate, and the dissemination of information and ideas.” First Nat’l Bank of Boston v. Bellotti, 435 U.S. 765, 775-76, 783 (1978).

16

Listeners need to be able to hear freely from both

sides of the debate. Critics of fossil fuel companies

speak prominently and freely, without worry of ruinous liability for statements about broad scientific

questions, notwithstanding the varied downstream

harms that would occur if they were wrong. For the

benefit of listeners, fossil fuel companies must be permitted to engage in public debate without fear of liability or double standards. The government “has no

* * * authority to license one side of a debate to fight

freestyle, while requiring the other to follow Marquis

of Queensberry rules.” R.A.V. v. City of St. Paul, 505

U.S. 377, 392 (1992).

Justice Breyer’s dissent, joined by Justice O’Connor, in Nike, Inc. v. Kasky, 539 U.S. 654 (2003), supports this as well. 2 Justice Breyer reasoned that Nike’s

public speech responding to criticisms of its production

processes was fully protected, because it “appear[ed]

outside a traditional advertising format, such as a

brief television or newspaper advertisement” and did

“not propose the presentation or sale of a product or

any other commercial transaction.” Id. at 665 (Breyer,

J., dissenting). Nike’s speech, Justice Breyer noted,

sought “to convey information to ‘a diverse audience,’

including individuals who have ‘a general curiosity

about, or genuine interest in,’ the public controversy

surrounding Nike.” Ibid. (citations omitted).

2 None of this Court’s members took the opposite view from this

opinion in Nike; this Court declined to consider the First Amendment question in that case for procedural reasons. See Nike, 539

U.S. at 655 (mem.) (per curiam).

17

And, most importantly, the content of Nike’s

speech made “clear that, in context, it concerns a matter that is of significant public interest and active controversy, and it describes factual matters related to

that subject in detail.” Ibid. Nike’s speech described

“Nike’s labor practices” and responded “to criticism of

those practices,” and did so “because those practices

themselves play an important role in an existing public debate” “in which participants advocated, or opposed, public collective action.” Ibid. “The First

Amendment’s protections of speech and press were

‘fashioned to assure unfettered interchange of ideas

for the bringing about of political and social changes.’”

Id. at 677-678 (Breyer, J., dissenting) (quoting Roth v.

United States, 354 U.S. 476, 484 (1957)). This was said

about speech discussing a company’s labor practices—

and the reasoning applies even more to discussions

about some of the weightiest scientific and political issues being debated by Americans today.

D. The First Amendment Protects Petitioning the Government.

What is true of companies’ speech to the public

extends equally to companies’ individual and collective

petitioning of governmental bodies. And this principle

likewise applies regardless of the economic self-interest behind the companies’ speech.

As this Court has long recognized, “it would be destructive of rights of association and of petition to hold

that groups with common interests may not, without

violating the antitrust laws, use the channels and procedures of state and federal agencies and courts to advocate their causes and points of view respecting

18

resolution of their business and economic interests visà-vis their competitors.” California Motor Transp. Co.

v. Trucking Unltd., 404 U.S. 508, 510-511 (1972). Indeed, as this Court noted, such speech was protected

in Noerr even though “[t]he political campaign operated by the railroads in Noerr to obtain legislation

crippling truckers employed deception and misrepresentation and unethical tactics.” Id. at 512.

“Congress has traditionally exercised extreme caution in legislating with respect to

problems relating to the conduct of political

activities, a caution which has been reflected

in the decisions of this Court interpreting

such legislation. All of this caution would go

for naught if we permitted an extension of the

Sherman Act to regulate activities of that nature simply because those activities have a

commercial impact and involve conduct that

can be termed unethical.”

Ibid. (quoting Noerr, 365 U.S. at 141).

To be sure, in the course of litigation, “unethical

conduct in the setting of the adjudicatory process often

results in sanctions.” Ibid. But the fact that Rule 11

leaves judges with considerable authority to sanction

filings that they view as frivolous and factually unfounded does not give the government authority to regulate speech outside litigation. Id. at 513 (“Misrepresentations, condoned in the political arena, are not immunized when used in the adjudicatory process.”). And

even when it comes to litigation, only “objectively baseless” litigation loses its First Amendment immunity,

regardless of its supposedly malign motivation.

19

Professional Real Estate Invs., Inc. v. Columbia Pictures Indus., Inc., 508 U.S. 49, 60-61 (1993).

The constitutional protection for petitioning the

government, and in particular, the EPA and other federal actors, is all the more reason to take a broad view

of federal preemption as it relates to this case. Even if

there was some question regarding field preemption

by federal environmental laws, the fact that States

and localities could punish companies for petitioning

the federal government would deprive such federal actors of the companies’ perspective on critical issues

subject to actual or potential regulation. Impeding the

flow of information to federal actors is in direct conflict

with the regulatory and legislative authority of those

actors.

E.

The First Amendment Protects Expressive Association.

The climate-change lawsuits also routinely rely

on defendants’ joining with others to speak, petition,

and litigate about fossil fuels. See, e.g., J.A.107-110,

¶¶ 422-435. As part of these theories, they seek discovery of all participation in various associations, as well

as communications within those associations. See, e.g.,

1st Req. Prod. of Docs. at 6 (¶ 17), 9-10 (¶¶ 16-17), City

& County of Honolulu v. Sunoco LP, No. 1CCV-200000380 (LWC) (Haw. Cir. Ct., 1st Cir. Aug. 26, 2024)

(seeking “Communications that occurred in the course

of Your participation in Trade Associations or other organizations” from 1950 to the present as well as the

identities of “all of Your current and former employees

who were Board or committee members * * * [and] all

Documents Concerning the governance structure,

20

organization, voting, rules, and policies for those organizations” from 1950 to the present); Pls.’ 1st Req.

Prod. of Docs., City of Annapolis v. BP P.L.C., No. C02-CV-21-000250 (Md. Cir. Ct., Anne Arundel Cnty.

Aug. 13, 2024) (similar); Pl.’s 1st Reqs. Prod. of Docs.

at 14-16 (¶¶ 27-28, 31-33), 24 (¶ 67), Vermont v. Exxon

Mobil Corp., No. 21-CV-02778 (Vt. Super. Ct. Oct. 13,

2025) (similar).

Yet “[t]he First Amendment * * * restricts the

ability of the State to impose liability on an individual

solely because of his association with another.”

Claiborne Hardware, 458 U.S. at 918-919 (so holding

specifically as to civil liability). “Regular attendance

and participation at * * * meetings” of a group, for instance, “is an insufficient predicate on which to impose

liability,” absent evidence of participation in planning

“illegal conduct,” such as violence (the issue in

Claiborne itself), antitrust conspiracy, and the like. Id.

at 924. And mere assertions of such conduct in connection with protected activities, and fishing expeditions

supposedly to unearth such conduct, should be viewed

with the usual skepticism of heightened scrutiny.

The First Amendment also recognizes “the ‘vital

relationship’ between ‘privacy in one’s associations’

and the ‘freedom to associate.’” First Choice Women’s

Res. Ctrs., Inc. v. Davenport, 146 S. Ct. 1114, 1123

(2026) (quoting NAACP v. Alabama ex rel. Patterson,

357 U.S. 449, 462 (1958)). “Strip away the ability of

individuals to work together free from governmental

oversight and intrusion, and the freedom to associate

may become no freedom at all—individuals deterred,

groups diminished, and their protected advocacy

21

suppressed.” Ibid. This logic applies equally to the

ability of businesses to work together for political

ends.

Restrictions on or penalties for association, including piercing the “privacy in one’s associations,”

make associating with others for political purposes a

perilous proposition, and undermine the “right to associate with others” in order “to speak, * * * publish,

* * * and petition.” “Government actions tending to

‘curtai[l] the freedom to associate’ warrant ‘the closest

scrutiny under the First Amendment.’” Id. at 11221123 (quoting NAACP, 357 U.S. at 460-461, and Americans for Prosperity Found. v. Bonta, 594 U.S. 595, 606

(2021)). Holding companies liable for the speech of

groups they join, or requiring them to disclose the

groups’ membership or their internal political communications, fails such scrutiny, just as this Court held

as to individuals in Claiborne Hardware.

In this case and others like it, the associations are

not being accused of organizing violence (the allegation in Claiborne), antitrust conspiracy, or other such

illegal conduct. They are being accused of speaking

about controversial scientific questions related to climate change. For the reasons given in Parts I.B-I.C

supra, such speech cannot itself be restricted. And for

the reasons given above, associating to engage in such

speech cannot be restricted, either.

F.

The First Amendment Protects the

Right Not to Speak

The climate-change lawsuits also often demand

that courts order defendants to fund public advocacy

campaigns supposedly aimed at correcting their

22

alleged misstatements. In this very lawsuit, plaintiffs

ask the court to order plaintiffs to pay “the cost of public education programs concerning responses to climate alteration.” J.A.138, ¶ 532. Likewise, the Connecticut lawsuit seeks an “order that ExxonMobil fund

a corrective education campaign to remedy the harm

inflicted by decades of disinformation.” 2d Am. Compl.

at 45, Prayer for Relief ¶ 5, Connecticut v. Exxon Mobil

Corp., No. HHD-CV20-6132568-S (Conn. Super. Ct.,

Hartford Cnty. Nov. 8, 2024); see also Compl. at 77,

Prayer for Relief ¶ 7.4, Leon v. Exxon, No. 25-2-159868-SEA (Wash. Super. Ct., King Cnty. May 29, 2025)

(seeking “an obligation to provide * * * a public education campaign to help rectify Defendants’ decades of

misinformation”); Compl. ¶ 246, Minnesota v. American Petroleum Inst., No. 62-CV-20-3837 (Minn. Dist.

Ct., Ramsey Cnty. June 24, 2020) (likewise).

But such a remedy would constitute an unconstitutional speech compulsion. “Generally, * * * the government may not compel a person to speak its own preferred messages.” 303 Creative LLC v. Elenis, 600 U.S.

570, 586 (2023). And “[c]ompelling a person to subsidize the speech of other private speakers raises similar

First Amendment concerns” to those raised by compelled speech. Janus v. American Fed’n of State, Cnty.

& Mun. Emps., 585 U.S. 878, 893 (2018). The protection against such compulsions also extends to businesses as well as individuals. See, e.g., Miami Herald

Publ’g Co. v. Tornillo, 418 U.S. 241, 256 (1974) (cited

as one of the supporting authorities in 303 Creative,

600 U.S. at 586); Pacific Gas & Elec. Co. v. Public

Utils. Comm’n of Cal., 475 U.S. 1, 8 (1986) (plurality

op.) (striking down a speech compulsion imposed on an

23

energy corporation, partly based on the principle that

“[t]he identity of the speaker is not decisive in determining whether speech is protected”). A court thus

may not require anti-fossil-fuel advocacy groups—or

any other kinds of advocacy groups—to publish, or to

fund publishing, purported corrections to fully protected public commentary just because judges or jurors conclude the commentary is misleading. See Parts

I.B-I.C supra (explaining why businesses’ speech on

climate change is indeed fully protected). The same is

true of requirements that climate-change lawsuit defendants express the views of their political adversaries.

To be sure, this Court’s “precedents have applied

more deferential review to some laws that require professionals to disclose factual, noncontroversial information in their ‘commercial speech.’” National Inst.

Fam. & Life Advocs. v. Becerra, 585 U.S. 755, 768

(2018) (NIFLA) (citing, among other cases, Zauderer,

471 U.S. at 651). But, for reasons given in Part I.C,

much of the speech that the climate-change lawsuit

plaintiffs target is not commercial, and the remedies

they seek are not limited to disclaimers in commercial

advertisements. And, as with the compelled speech related to abortion in NIFLA, the subject of climate

change is “anything but an ‘uncontroversial’ topic.” Id.

at 769.

Likewise, as in NIFLA, a plaintiff in a climatechange case “could inform [the public] about [its views

on climate change] ‘without burdening a speaker with

unwanted speech.’” Ibid. (quoting Riley v. National

Fed’n of Blind of N.C., Inc., 487 U.S. 781, 800 (1988)).

That it would have to raise money for such speech from

24

its own supporters rather than from its opponents is

precisely how a marketplace of ideas should work, as

opposed to a centralized speech economy with the

funding of favored ideas directed and compelled by the

government or the courts.

II. Imposing Liability for Interstate and International Activity Based on the Local Downstream Consequences of Such Extraterritorial Behavior Is Beyond the Power of Individual States Under the Foreign Commerce

Clause.

Besides the serious First Amendment concerns favoring a broad preemption ruling that would avoid

such constitutional problems, the state-law suits in

this case and others around the country seek to regulate national and international commerce in violation

of the Commerce Clause and related structural constraints on extraterritorial regulation.

Boulder attempts to penalize multinational companies not merely for the local and immediate consequences of any local operations, but for the multicausal long-term consequences of their sales and

speech around the country and around the globe. And

it is seeking to impose liability on Suncor for the joint

consequences of millions of decisions by actors beyond

its borders, operating in interstate and international

trade. Whatever reticence this Court might have in

preempting largely ordinary State regulation that incidentally affects interstate commerce, that reticence

would be misplaced when it comes to such a major encroachment on international commerce and an attempt to impose Boulder’s views of nuisance and

25

appropriate speech on actors not just in other States

but also in foreign countries.

For good reasons, this Court has understood Congress’s delegated power over foreign commerce as exclusive of State powers. That understanding is consistent with the original public meaning of both the

delegation of power to Congress in Article I, and the

catch-all reservation of powers to the states and the

people in the Tenth Amendment.

Regardless whether the Constitution supports the

somewhat variable dormant interstate Commerce

Clause as it had evolved over the years, a more textually grounded reading of the clause supports exclusive

federal authority here. Boulder’s attempt to impose

Colorado law on interstate and foreign commerce conflicts with the Commerce Clause, Article I’s delegation

of powers, and the Tenth Amendment. And it more

broadly conflicts with the Constitution’s structure,

which organizes horizontal relations among States on

principles of (partial) state autonomy, equality, territoriality, non-aggression, and mutual recognition.

The power to “regulate Commerce with foreign

Nations, and among the several States, and with the

Indian Tribes” U.S. Const. art. I, § 8, cl. 3, is one of the

“legislative Powers” that the Constitution “grant[s],”

and promises will be “vested in[,] a Congress of the

United States,” U.S. Const. art. I, § 1.

As a textual matter Article I’s grant of authority

is exclusive. Taking the “words * * * in their natural

and obvious sense, and not in a sense unreasonably restricted or enlarged,” Martin v. Hunter’s Lessee, 14

U.S. (1 Wheat.) 304, 326 (1816), any “legislative

26

power” granted “is * * * absolutely vested,” id. at 329.

And by vesting powers in Congress, the Constitution

divested those same powers from the States. As Justice Story explained in Hunter’s Lessee, “the sovereign

powers vested in the state governments, by their respective constitutions, remained unaltered and unimpaired, except so far as they were granted to the government of the United States.” Id. at 325 (emphasis

added).

The text of the Tenth Amendment confirms this

reading, providing that “[t]he powers not delegated to

the United States by the Constitution, nor prohibited

by it to the States, are reserved to the States respectively, or to the people.” U.S. Const. amend. X (emphasis added). By such wording the Tenth Amendment

necessarily recognizes that powers that are delegated

to the United States are not “reserved” to the States or

the people, but reside solely in the federal government.

Congress might exercise its power to seek assistance

from, or grant permission for, some state activities

properly understood to “regulate” interstate or foreign

commerce. But the default rule is the absence of state

power to regulate interstate and foreign commerce—

not endless state encroachment on delegated national

authority unless and until Congress affirmatively says

otherwise.

And that is true even though Congress has the undoubted option to affirmatively disable state regulation of extraterritorial commerce. The exercise of national legislative authority was designed to be difficult. Hurdles such as bicameralism, the potential veto,

and the volume of matters that compete for Congress’s

attention slow and often stop such exercise. Default

27

rules are thus important, and the constitutional default for Article I powers is that individual States may

not take it upon themselves to exercise powers delegated to Congress. The Constitution sought to free foreign commerce from state mischief, not to preserve all

opportunity for such mischief while the national legislative process struggles to keep up.

Consistent with a proper reading of the Constitutional text, this Court’s early cases rejected any suggestion that the power to regulate extraterritorial

commerce was held concurrently by Congress and the

States.

In Gibbons v. Ogden, Daniel Webster argued that

it would be “insidious and dangerous” for the States to

have a “general concurrent power” with Congress that

would allow the States to “do whatever Congress has

left undone.” 22 U.S. (9 Wheat.) 1, 17-18 (1824). This

Court did not need to reach that question in Gibbons,

id. at 208-212, but several justices did discuss it in the

Passenger Cases, addressing fees imposed by New

York on ships carrying people traveling into the State.

Smith v. Turner, 48 U.S. (7 How.) 283 (1849) (Passenger Cases). Justice McLean extensively reviewed the

various powers delegated to Congress, the necessity of

their exclusiveness within the narrow confines of such

delegations, and concluded:

Whether I consider the nature and object of

the commercial power, the class of powers

with which it is placed, the decision of this

court in the case of Gibbons v. Ogden, reiterated in Brown v. The State of Maryland, and

often re-asserted by Mr. Justice Story, who

28

participated in those decisions, I am brought

to the conclusion, that the power “to regulate

commerce with foreign nations, and among

the several States,” by the Constitution, is

exclusively vested in Congress.

Id. at 400.

Justice Story, for his part, spoke of one State’s

“cheerful acquiescence” in the exclusivity of the commerce power, a point he said had not been “seriously

controverted.” 2 Joseph Story, Commentaries on the

Constitution of the United States 515, § 1067 (Bos.,

Hilliard, Gray & Co. 1833), https://tinyurl.com/

4xx3aavj. He explained that the “power to regulate

commerce is general and unlimited in its terms” and

left “no residuum” to the States. Id. at 513, § 1063. He

continued that “when a State proceeds to regulate

commerce with foreign nations, or among the several

states, it is exercising the very power, which is granted

to congress; and is doing the very thing which congress

is authorized to do.” Id. at 514, § 1064.

The power to tax, by contrast, is different. Congress originally was empowered to adopt “uniform”

taxes “throughout the United States” to pay for distinctly national obligations and activities “of the

United States.” U.S. Const. art. I, § 8, cl. 1. States may

tax only within their jurisdiction and they do so for different ends. “In imposing taxes for state purposes, a

state is not doing what congress is empowered to do.”

2 Story, supra at 513, § 1064.

Especially in cases involving foreign commerce,

this Court has described the commerce power as an

exclusive delegation. In Crutcher v. Kentucky, 141 U.S.

29

47 (1891), this Court explained that the “prerogative,

the responsibility, and the duty of providing for the security of the citizens and the people of the United

States in relation to foreign corporate bodies or foreign

individuals with whom they may have relations of foreign commerce, belong to the government of the

United States, and not to the governments of the several states.” Id. at 58.

This Court eventually moved away from its earlier understanding as to exclusive federal power over

interstate commerce, discovering the very “residuum

of power” in the States to act in “the absence of conflicting legislation by Congress,” Southern Pac. Co. v.

Arizona ex rel. Sullivan, 325 U.S. 761, 767 (1945), that

Joseph Story rejected in his Commentaries. But this

Court nonetheless continued to recognize greater exclusive Congressional authority as to foreign commerce, concluding that the federal “power when exercised in respect of foreign commerce may be broader

than when exercised as to interstate commerce.” Atlantic Cleaners & Dyers v. United States, 286 U.S. 427,

434 (1932).

In Atlantic Cleaners, this Court explained its conclusion that the Commerce Clause could be plenary as

to foreign commerce but not as to interstate commerce

by noting that “there is no rule of statutory construction” that precluded it from treating the “same word”

as though it has “different meanings.” Id. at 433. 3 And

3 A genuinely originalist and textualist reading would recognize

that the Commerce Clause, at least at its core and not expanded

beyond its terms over the years, is exclusive as to interstate commerce as well. But this Court’s reluctance to return to the original

meaning of the Commerce Clause in the interstate commerce

30

indeed there is some “evidence that the Founders intended the scope of the foreign commerce power to be

the greater.” Japan Line, Ltd. v. Los Angeles County,

441 U.S. 434, 448 (1979).

Even taking those cases rejecting the exclusivity

of the interstate commerce power on their own terms,

any residuum of power left with the States was limited

and would apply only to “matters of local concern” that

would “in some measure affect interstate commerce”

or “to some extent, regulate it.” Southern Pac., 325

U.S. at 767 (collecting cases). For that reason, just over

a decade after this Court decided Southern Pacific, it

could still say, correctly, that its cases recognized that

the “Commerce Clause gives exclusive power to the

Congress to regulate interstate commerce, and its failure to act on the subject in the area of taxation nevertheless requires that interstate commerce shall be free

from any direct restrictions or impositions by the

States.” Northwestern States Portland Cement Co. v.

Minnesota, 358 U.S. 450, 458 (1959) (emphasis added)

(citation omitted). In the foreign commerce context,

this Court should be even more cautious in permitting

direct or indirect burdens on international commerce.

The subsequent tendency to find even more exceptions to interstate commerce exclusivity—adding more

judicial policymaking into the mix—was perhaps

driven by concerns that an exclusive reading of an

ever-expanding commerce power would foreclose too

many state laws regulating ordinary local matters

context should not prevent it from maintaining the original

meaning of the Clause in the foreign commerce context, consistent with its past precedent in this area.

31

that in some way had an effect on interstate commerce.

But while such concerns are understandable, they

arise from a different error, not from a proper understanding of exclusivity.

Under an original and narrower view of the commerce power (apart from the erroneously expansive

gloss of the Necessary and Proper Clause), any problem of excessively disabling state powers would have

been limited. Cf. Albert S. Abel, The Commerce Clause

in the Constitutional Convention and in Contemporary

Comment, 25 Minn. L. Rev. 432, 493 (1941) (“On the

whole, the evidence supports the view that, as to the

restricted field which was deemed at the time to constitute regulation of commerce, the grant of power to

the federal government presupposed the withdrawal

of authority pari passu from the states.”). As Justice

Thomas has explained, the “Clause’s text, structure,

and history all indicate that, at the time of the founding, the term ‘“commerce” consisted of selling, buying,

and bartering, as well as transporting for these purposes.’” Gonzales v. Raich, 545 U.S. 1, 58 (2005)

(Thomas, J., dissenting) (quoting United States v.

Lopez, 514 U.S. 549, 585 (1995) (Thomas, J., concurring))).

When the commerce power is properly constrained to those activities, any alleged harm from divesting the States of such power is necessarily cabined. “While in its content the commerce clause was

designed to include only a limited number of matters,

the states could no more legislate with propriety as to

subjects falling within its limits than Congress could

as to any subjects falling outside them.” Abel, supra,

25 Minn. L. Rev. at 494.

32

Just as this Court has recognized that the vesting

of powers in one branch forecloses exercise of or encroachment on such powers by another branch in the

context of horizontal separation of powers, so too it

should continue to recognize a vertical separation of

powers between the federal government and the

states, especially concerning the exclusive federal

power to regulate foreign commerce. Plaintiffs’ attempt to extend their tort laws to encompass extraterritorial conduct and global consequences reaches well

into the regulation of foreign commerce that is the exclusive province of the federal government.

CONCLUSION

Recognizing, for the reasons given in petitioners’

brief, that respondents’ claims are preempted by

federal law will, among other things, help avoid the

serious First Amendment problems and Foreign

Commerce Clause problems that climate-change

plaintiffs’ theories would yield. The judgment of the

Colorado Supreme Court should therefore be reversed.

33

Respectfully submitted,

EUGENE VOLOKH

Counsel of Record

SCHAERR | JAFFE LLP

One Embarcadero Center

Suite 1200

San Francisco, CA 94111

Telephone: (415) 562-4942

evolokh@schaerr-jaffe.com

ERIK S. JAFFE

SCHAERR | JAFFE LLP

1717 K Street NW, Suite 900

Washington, DC 20006

Telephone: (202) 787-1060

ejaffe@schaerr-jaffe.com

Counsel for Amicus Curiae

MAY 21, 2026