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

Supreme Court briefMay 21, 2026

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No. 25-170

In the

Supreme Court of the United States

♦

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

Petitioners,

COUNTY COMMISSIONERS OF BOULDER COUNTY, ET AL.,

Respondents.

♦

On Writ of Certiorari to the

Supreme Court of Colorado

♦

AMICI CURIAE BRIEF BY

PROFESSOR RICHARD EPSTEIN AND

PROFESSOR JOHN YOO

IN SUPPORT OF PETITIONERS

♦

Ivan L. London

Counsel of Record

MOUNTAIN STATES

LEGAL FOUNDATION

2596 South Lewis Way

Lakewood, Colorado 80227

(303) 292-2021

ilondon@mslegal.org

May 21, 2026

Attorney for Amici Curiae

TABLE OF CONTENTS

Page(s)

TABLE OF CONTENTS .....................................

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

IDENTITIES AND INTERESTS OF

AMICI CURIAE ..................................................

SUMMARY OF THE ARGUMENT....................

ARGUMENT .......................................................

Respondents Are Using Technical

Arguments to Avoid a Merits Decision ....

II.

The Decision Below Misstates

the Law of Preemption and

Should Be Reversed..................................

Respondents Cannot Plead Any

Valid Tort Claims .....................................

A. Respondents have failed to

identify a proper defendant ................

B. There is no materiality or

causation .............................................

C. Respondents cannot show any

basis for justifiable reliance................

CONCLUSION ....................................................

III.

TABLE OF AUTHORITIES

Cases

Page(s)

American Electric Power v. Connecticut,

564 U.S. 410 (2011) ....................

4, 6, 7, 8, 9, 10

American Insurance Association v.

Garamendi,

539 U.S. 396 (2003) ..........................................

Ashcroft v. Iqbal,

556 U.S. 662 (2009) ..........................................

Bell Atlantic, Corp. v. Twombly,

550 U.S. 544 (2007) ..........................................

Boyle v. United Technologies Corp.,

487 U.S. 500 (1988) ..........................................

Burgess v. M/V Tamano,

370 F. Supp. 247 (D. Me. 1973) .......................

City & Cnty. of Honolulu v. Sunoco LP,

537 P.3d 1173 (Haw. 2023) .............................. 2, 20

City of Chicago v. Beretta U.S.A. Corp., 821

N.E.2d 1099 (Ill. 2004) .....................................

City of New York v. Chevron Corp.,

993 F.3d 81 (2d Cir. 2021) ...............................

2, 8

iii

Clearfield Trust Co. v. United States,

318 U.S. 363 (1943) ..........................................

8, 9

Cox Broadcasting Corp. v. Cohn,

420 U.S. 469 (1975) ..........................................

Crosby v. National Foreign Trade Council,

530 U.S. 363 (2000) ..........................................

Derry v. Peek,

L. R. 14 App. Cas. 337 (1889) ....................................

Erie R.R. Co. v. Tompkins,

304 U.S. 64 (1938) ............................................

8, 9

Express Scripts, Inc. v. Anne Arundel

County,

353 A.3d 1084 (Md. 2026) ................................ 18, 27

Hencely v. Fluor Corp,

146 S.Ct. 1086 (2026) ....................................... 15, 16

Hinderlider v. La Plata River & Cherry

Creek Ditch Co.,

304 U.S. 92 (1938) ............................................

Hines v. Davidowitz,

312 U.S. 52 (1941) ............................................

Illinois v. City of Milwaukee,

406 U.S. 91 (1972) ............................................ 9, 16

Mayor & City Council of Baltimore v.

B.P. P.L.C.,

353 A.3d 1142 (Md. 2026) ................................

McCulloch v. Maryland,

17 U.S. (4 Wheat.) 316 (1819) ..........................

Osborn v. Bank of the United States,

22 U.S. (9 Wheat.) 738 (1824) ..........................

State ex rel. Hunter v. Johnson & Johnson,

499 P.3d 719 (Okla. 2021) ................................

Ultramares Corp. v. Touche,

174 N.E. 441 (N.Y. 1931) .................................

Statutes

28 U.S.C. § 1257(a)..............................................

42 U.S.C. § 9613(f) .............................................. 23, 24

Regulations

Endangerment and Cause or Contribute

Findings for Greenhouse Gases Under

Section 202(a) of the Clean Air Act,

74 Fed. Reg. 66,496 (Dec. 15, 2009).................

Other Authorities

Anonymous, Y.B. Mich., 27 Hen. 8, f. 27, pl.

10 (King’s Bench 1536) ....................................

Carbon Monitor, https://carbonmonitor.org/ ......

Kyoto Protocol to the United Nations Framework

Convention on Climate Change, Dec. 10, 1997, 2303

U.N.T.S. 162 ................................................................ 12, 13

Paris Agreement to the United Nations

Framework Convention on Climate Change,

Dec. 12, 2015, T.I.A.S. No. 16-1104 .................

Praise of Erie—And of the New Federal

Common Law, 39 N.Y.U. L. REV. 383,

421–22 (1964) ...................................................

Restatement (Second) of Torts: Liability for

Economic Harm ..........................

19, 23, 24

Restatement (Third) of Torts: Liability for

Economic Harm ................................................

The Private Law Connections to Public

Nuisance Law: Some Realism About

Today’s Intellectual Nominalism,

17 J.L. Econ. & Pol’y 282 (2022) ......................

United Nations, IPCC report: ‘Code red’ for

human driven global heating, warns UN

chief (Aug. 9, 2021),

https://news.un.org/en/story/2021/08/10973

62 ......................................................................

U.S. Energy Information Administration,

State Energy Data System 1960–2021:

Prices and Expenditures (2023) .......................

IDENTITIES AND INTERESTS

OF AMICI CURIAE1

Professor Richard A. Epstein is the Laurence A.

Tisch Professor of Law at New York University. He is

also a Senior Fellow at the Civitas Institute, and the

James Parker Hall Distinguished Service Professor

Emeritus of Law and Senior Lecturer at the

University of Chicago Law School. Professor Epstein

is one of the foremost scholars in the United States on

tort and takings law, and he maintains a unique

interest in ensuring that courts appropriately apply

basic tort doctrine to the rapidly evolving field of

public nuisances.

Professor John Yoo is the Emanuel S. Heller

Professor of Law at the University of California at

Berkeley and Faculty Director of its Law & Public

Policy Program. He also serves as Senior Research

Fellow, Civitas Institute, University of Texas at

Austin; and Non-resident Senior Fellow at the

American Enterprise Institute. He maintains a

unique interest and expertise in ensuring that courts

apply preemption doctrine appropriately.

♦

1 No counsel for a party authored this brief in whole or in part,

and no such counsel or party made a monetary contribution

intended to fund the preparation or submission of the brief.

SUMMARY OF THE ARGUMENT

If the global and national climates are

changing, then the Nation should decide collectively

through legislation and administrative orders how

best to address the changes. See City of New York v.

Chevron Corp., 993 F.3d 81, 91 (2d Cir. 2021) (“[T]he

question before us is whether a nuisance suit seeking

to recover damages for the harms caused by global

greenhouse gas emissions may proceed under New

York law. Our answer is simple: no.”) (New York).

Neither Boulder, Colorado, nor other state and local

actors applying state and local common law and

statutes can decide climate and energy policy for the

entire Nation.

This point seems obvious. Yet facing the

question “who gets to decide,” federal and state courts

are struggling with the answer. Approximately sixty

lawsuits like this one have been filed. Among the

lawsuits, the Court of Appeals for the Second Circuit

has rejected local attempts to manufacture common

law claims to address alleged injuries arising (albeit

only indirectly) from greenhouse gas emissions. New

York, 993 F.3d at 91. But the Supreme Court of

Hawaii has in turn rejected the Second Circuit

decision for its supposedly “flawed reasoning.” City &

Cnty. of Honolulu v. Sunoco LP, 537 P.3d 1173, 1196

(Haw. 2023) (Hawaii).

Amidst this conflict in the courts, the dispute

comes to this Court from Boulder, Colorado, whose

court of last resort followed Hawaii in rejecting the

Second Circuit. This Court took the case to resolve

this conflict that has spread its tentacles across the

Nation.

The case raises three questions to the Court:

(I) whether the Court should hear this case now;

(II) whether federal law preempts these state

lawsuits; and (III) whether the underlying tort claims

have merit? The resolution in this forum should be

clear. Decades of federal common and statutory law,

acknowledged, interpreted, and applied by this

Court’s precedents, require ending these novel tort

claims now on their pleadings.

Underlying the central issue of preemption—

and really, all three questions—is the question of the

merits of the tort claims. Respondents have failed to

link recovery in this case with any actual emissions of

carbon dioxide. Instead, they have sought to go back

several links in the chain of fuel distribution to claim

that the ordinary sales of the energy products in

Colorado and elsewhere have allegedly caused losses

within their state, even though all users of energy

have received warnings from many sources of the

supposed risks of climate change.

But this claim styled as “misrepresentation”—

because Respondents cannot allege public nuisance—

satisfies none of the standard requirements for either

misrepresentation or nondisclosure. That is a

compelling reason to stop cases like this one at the

pleading stage with a final judgment against

Respondents now.

No matter how they try to mask their aims,

Respondents want to misuse the settled laws of

nuisance and misrepresentation against Petitioners

in this case and several others like it to set nationwide

climate policy, all in violation of sound tort principles.

The emptiness of Respondent’s “claims” means that a

judgment against all plaintiffs—Respondents here—

is warranted on the strength of the current record.

This case is thus ripe for a final judgment on appeal

under 28 U.S.C. § 1257(a).

Federal preemption is necessary to prevent

Respondents from co-opting nationwide climate

policy. Congress displaced local attempts to address

nationwide climate issues in the Clean Air Act. See

American Electric Power v. Connecticut, 564 U.S. 410,

422–23 (2011) (AEP). No state or local government

can use a set of fanciful lawsuits under state common

law to set nationwide climate and energy policy.

ARGUMENT

Respondents Are Using Technical

Arguments to Avoid a Merits Decision.

The Court can act on this case now.

Respondents seek to expand the scope of state public

nuisance to include the simple selling of gasoline in

Colorado. Petitioners allegedly become responsible for

adverse consequences said to follow from carbon

dioxide emissions. These tort claims have received a

mixed reception in the courts. The question is teed up

in at least sixty courts, with more to come.

So with the fate of this nation’s energy industry

and environment in the balance, the Court must rule

on this case’s merits now. Yet, Respondents

nevertheless make the opaque claim that this Court

lacks jurisdiction to hear this case because the

decision of the Colorado Supreme Court is

interlocutory and not fit for review.

The rule against hearing interlocutory appeals

should not apply in this case. The basic rule makes

good sense where there is a wide range of questions

such that the resolution of one issue selected for

appeal leaves the remainder of the case in limbo. But

its presumption does not hold where, as here, the

issue that has been isolated for appeal disposes of the

entire case without having to conduct expensive trials

that will consume judicial resources in multiple courts

for years.

It is for that reason that the Court’s bedrock

decision in Cox Broadcasting Corp. v. Cohn, 420 U.S.

469, 476–87 (1975), allows needed appeals to precede

exhaustive trials. Consider this case in light of Cox

Broadcasting: here, Respondents’ only motive in

insisting that the case is not ripe for appeal is to

generate another chapter in the endless procedural

maneuvering designed to force Petitioners to settle.

Put a different way, a question of jurisdiction at

this point might make sense if the merits of the case

were lopsided in favor of Respondents or if the matters

at issue did not interfere with the structure of

domestic and international energy markets. Not only

is the case for preemption here powerful, but also

Respondents have not stated a viable cause of action

for any theory of misrepresentation or nondisclosure.

Why remand?

II.

The Decision Below Misstates the Law of

Preemption and Should Be Reversed.

The Court should hold that federal common and

statutory law preempts the claims here. Respondents

filed tort claims against Petitioners (which are energy

companies) based on harms they allegedly have

suffered due to global climate change. They argue

Petitioners are at fault because they played some role

in increasing the concentration of greenhouse gases in

the global atmosphere, thereby playing some

indefinite, microscopic part in global climate change.

See Pet.App.25a–26a (Samour, J., dissenting).

This Court should reject the Colorado Supreme

Court’s holding and the precedents on which it relied.

The Court has already explained that the production,

sale, and consumption of fossil fuels in any single

state (or anywhere in the world) do not generate a

sufficiently large temperature change to produce a

rise in sea levels anywhere, let alone in any single city

or state. “Greenhouse gases once emitted ‘become well

mixed in the atmosphere.’” AEP, 564 U.S. at 422

(quoting Endangerment and Cause or Contribute

Findings for Greenhouse Gases Under Section 202(a)

of the Clean Air Act, 74 Fed. Reg. 66,496, 66,514 (Dec.

15, 2009)).

Disregarding this Court’s statement in AEP,

the Colorado Supreme Court instead offered a

convoluted mishmash of torts of public nuisance,

private nuisance, strict liability failure to warn,

negligent failure to warn, and trespass against

Petitioners. In doing so, the court replaced this

Court’s finding in AEP with a finding of potential tort

liability on the erroneous ground that greenhouse gas

emissions in Colorado or elsewhere raise worldwide

temperatures, which allegedly may cause weather

changes that maybe harm Colorado.

As was explained to this Court more than a

decade ago, “emissions in [New York or] New Jersey

may contribute no more to flooding in New York than

emissions in China.” AEP, 564 U.S. at 422. The same

is true for any supposed harm to Colorado. So the

Colorado Supreme Court’s embrace of the reasoning

in Hawaii erroneously repeats a theory rejected by

this Court in AEP and by the Second Circuit in New

York. The court mistakenly concluded instead that

federal law does not preempt Respondents’ state tort

law claims because the Clean Air Act had “displaced”

federal common law. While pre-Act federal common

law had allowed states to sue each other over air and

water pollution, AEP held that the Act displaced that

law. The Colorado Supreme Court, however, erred by

holding that the Clean Air Act’s displacement of a

judicially created federal common law cause of action

somehow allowed states to manufacture their own

novel common law actions on the same question.

That’s simply wrong. The court should have

read the Clean Air Act’s displacement of federal

common law as also extinguishing any state law

causes of action. As the Second Circuit found, AEP

does not authorize state law to snap back into place

“simply because Congress saw fit to displace a federal

court-made standard with a legislative one.” New

York, 993 F.3d at 98. Rather, the Act made the EPA

the “primary regulator of [domestic] greenhouse gas

emissions,” id. at 99 (citing AEP, 564 U.S. at 428), and

states only can regulate internal emissions sources,

not those from other states, id. at 100 (citing AEP, 564

U.S. at 422). This Court should reaffirm that, as the

Second Circuit correctly held, states cannot “utilize

state tort law to hold multinational oil companies

liable for the damages caused by global greenhouse

gas emissions.” New York, 993 F.3d at 85.

Moreover, while Erie R.R. Co. v. Tompkins, 304

U.S. 64 (1938), denied the existence of a general

federal common law, it also explicitly affirmed the

existence of a specialized federal common law where

national concerns are paramount. And Hinderlider v.

La Plata River & Cherry Creek Ditch Co., 304 U.S. 92

(1938), decided on the same day as Erie, held that

interstate water disputes are “a question of ‘federal

common law’ upon which neither the statutes nor the

decisions of either State can be conclusive.” Id. at 110.

In the absence of a federal common-law rule, the

states in a dispute would presumably give priority to

their own laws. Justice William O. Douglas expressed

the same view in Clearfield Trust Co. v. United States,

318 U.S. 363, 367 (1943) (applying federal common

law to deal with commercial paper to avoid “making

identical transactions subject to the vagaries of the

laws of the several states.”). And as Judge Henry

Friendly observed, “‘[e]nvironmental protection is

undoubtedly an area ‘within national legislative

power,’ one in which federal courts may fill in

‘statutory interstices,’ and, if necessary, even ‘fashion

federal law.’” AEP, 564 U.S. at 421 (quoting Henry

Friendly, In Praise of Erie—And of the New Federal

Common Law, 39 N.Y.U. L. REV. 383, 421–22 (1964)).

Indeed, a century of this Court’s precedent,

including Illinois v. City of Milwaukee, 406 U.S. 91,

102–03, 102 n.3 (1972), recognizes that federal

common law must govern here. As this Court

observed, interstate pollution presents an “overriding

. . . need for a uniform rule of decision” because states

have conflicting self-interests, energy production and

pollution are nationwide in scope, and the basic

interests of federalism are involved. Id. at 105 n.6.

The federal common law as it existed before the Clean

Air Act would have preempted the state tort claims in

this case.

AEP did not hold that the Clean Air Act revived

the state causes of action that earlier federal law had

preempted. AEP’s conclusion that the Act preempts

judge-made federal causes of action applies with even

greater force to state-made causes of action. “The

critical point is that Congress delegated to EPA . . .

whether and how to regulate carbon-dioxide

emissions [which] displaces federal common law.”

AEP, 564 U.S. at 426. And here, federalism plays an

important role. The lower federal courts are part of a

unified judicial system that can correct deviations

from established tort doctrine under a wellestablished body of federal law. By contrast, the state

courts are autonomous and can develop tort law

subject only to a weak set of constitutional

constraints. State tort law can create higher levels of

undesirable variation, as shown by the unprecedented

tort theory adopted by trial and appellate courts in

Hawaii and Colorado.

Adoption of AEP’s rule, moreover, would not

unconstitutionally intrude into the proper scope of

state authority under the Constitution’s system of

federalism. Under the Articles of Confederation,

states had erected tariffs, duties, and trade barriers

that prevented a free trade area within the United

States. As Gordon Wood has described the impetus for

constitutional reform in the 1780s, “it was ‘the

corruption and mutability of the Legislative Councils

of the States’ the ‘evils operating in the States,’ that

actually led to the overhauling of the federal

government in 1787.” Gordon S. Wood, The Creation

of the American Republic, 1776-87, at 467 (1969). “The

federal Constitution became the culmination of a

decade’s efforts by Americans to readjust their

constitutional structures to fit what Hamilton called

‘the commercial character of America.’” Id. The

Constitution gave the federal government the

authority to regulate interstate commerce while also

prohibiting states from laying “Imposts or Duties on

Imports or Exports.” It sought to prevent the states

from engaging in harmful regulatory competition and

a cycle of retaliatory sanctions that would punish free

trade between the states.

Overruling the court in this case would prevent

Colorado from exercising extraterritorial control over

behavior the vast majority of which takes place in the

rest of the Nation. If Colorado governments impose an

effective tax on economic activity that takes place in

other states, then those states will respond—without

federal intervention—with similar taxes of their own.

Extraterritorial application of Colorado law would

spark the very cycle of harmful economic retaliation

that the Framers wanted to suppress.

Properly concerned with the tension between

federal and state authority, the Framers of the

Constitution wisely crafted a balanced system that

prevents a single state from regulating a nationwide

industry. Applying AEP’s rule serves the interests of

federalism by keeping orderly relations among the

states while reserving federal government control

over interstate pollution and nationwide industry.

This Court should also maintain federal

common law preemption over interstate aerial

pollution due to the foreign policy and national

security interests at stake. This Court has long

recognized that the Constitution vests the conduct of

foreign relations in the federal government alone. See,

e.g., Hines v. Davidowitz, 312 U.S. 52, 63 (1941). It has

preempted state laws that might interfere with

federal foreign policy, even in the absence of a treaty.

In Crosby v. National Foreign Trade Council, 530 U.S.

363 (2000), for example, this Court preempted a state

law that imposed sanctions on Burmese-related goods

because it conflicted with federal foreign policy toward

Burma.

This Court has further held that states cannot

use their police powers to regulate areas that are the

subject of diplomatic negotiations by the federal

government. In American Insurance Association v.

Garamendi, 539 U.S. 396 (2003), this Court held that

the federal common law of foreign relations

preempted a California law that required insurers to

disclose information relating to pre-WWII insurance

policies held by Swiss and German companies. The

Court found that the state law conflicted with the

Clinton administration’s diplomatic efforts to achieve

a settlement between the German government,

financial institutions, and Holocaust survivors and

their families.

In a similar way, these air pollution cases

directly impact national foreign policy interests. The

executive branch has entered into international

agreements designed to regulate greenhouse gas

emissions and has participated in international

negotiations to identify areas for cooperation between

nations. See, e.g., Paris Agreement to the United

Nations Framework Convention on Climate Change,

Dec. 12, 2015, T.I.A.S. No. 16-1104; Kyoto Protocol to

the United Nations Framework Convention on

Climate Change, Dec. 10, 1997, 2303 U.N.T.S. 162;

Rio Declaration on Environment and Development,

Jun. 13, 1992, 31 ILM 874 (1992). Respondents

attempt to impose a damages sanction on Petitioners

for the very conduct, based on the same theory of

harm, that is the focus of these national diplomatic

efforts. The potential interference with federal foreign

policy further demonstrates the need to preempt the

state causes of action in this case.

The national security interests at stake are of

the highest order. Controlling energy has long

constituted an important national security goal that

not only supports economic independence and

stability but also U.S. diplomacy and military

capabilities. If this Court were to allow these tort

cases to proceed, then states and localities could

handicap an interstate industry critical to the

Nation’s economy and security.

Development of energy resources makes a

critical contribution to American security. It not only

supplies the fuel for military operations themselves,

but it also underpins the growing economy necessary

to provide the resources for national defense. In 2021,

the energy industry employed 7.8 million Americans;

in 2022, employment rose to 8.1 million. 2 Americans

last year spent $1.3 trillion on energy, which amounts

United States Energy and Employment Report 2023.

https://www.energy.gov/media/299601, last visited May 19, 2026.

to 5.7% of the Gross Domestic Product. U.S. Energy

Information Administration, State Energy Data

System 1960–2021: Prices and Expenditures (2023).

There are more than 11,000 utility-scale power plants

in this Nation that deliver electricity to the Nation’s

power grid. 3

Conversely, weakness in the U.S. energy sector

can harm American security. State laws that burden

oil and gas production can reduce the resources

available to defense and create vulnerabilities to

enemy attack or pressure. During the 2026 conflict

between the United States and Iran, the U.S. Armed

Forces destroyed most of Iran’s military assets and

established air superiority in the skies. Iran

responded by blockading the Straits of Hormuz—

through which about 20% of world oil supplies pass—

to increase energy prices and place economic pressure

on the United States and its allies. American

increases in oil and gas production, which have made

the United States energy-self-sufficient, may have

reduced the direct impact of Iran’s blockade on the

Nation. But Iran’s interdiction of oil exports from the

Persian Gulf still pressured oil markets worldwide,

which increased Tehran’s bargaining leverage.

Allowing states to interfere with national oil and gas

markets would increase the Nation’s vulnerability to

the energy blackmail practiced by Iran.

3 https://www.epa.gov/power-sector/electric-power-sector-basics,

last visited May 18, 2026.

Further, this Court’s recent decision in Hencely

v. Fluor Corp., 146 S.Ct. 1086 (2026), is not to the

contrary. In Hencely, this Court declined to extend the

preemption of state product liability claims against

military contractors to injuries that stemmed from

activities on the battlefield. In Boyle v. United

Technologies Corp., 487 U.S. 500 (1988), this Court

had held such preemption proper only when the

manufacturer had to follow the design specifications

demanded by a government contractor. In Hencely,

this Court found that neither the Constitution nor

statutes preempted all hypothetical state lawsuits by

a contractor involving combatant activities. Hencely,

146 S.Ct. at 1093.

The Hencely majority and dissent, however,

agreed that the structure of the Constitution itself

could require preemption of state laws. As Justice

Thomas’s opinion observed, Boyle recognized that “a

few areas, involving ‘uniquely federal interests,’ are so

committed by the Constitution and the laws of the

United States to federal control that state law is

preempted and replaced, where necessary, by federal

law.” Id. at 1094. Justice Alito’s dissent agreed. “We

have long recognized that federal law preempts state

laws that intrude on the powers that the Constitution

confers exclusively on the Federal Government, as

well as laws that substantially interfere with the

operation of the Federal Government’s organs or the

work of federal officers.” Id. at 1101 (Alito, J.,

dissenting).

This case presents the opposite situation from

Hencely. Here, this Court has already recognized the

preemption of state regulation of interstate pollution.

See Milwaukee, 406 U.S. at 102–03, 102 n.3. This case

does not present the Court with the question whether

to extend federal preemption to a new area. Rather, it

asks whether, when Congress enacted the Clean Air

Act, it also reversed the preemption of state laws

affecting interstate pollution that had governed for a

century. Congress did not explicitly override the

entire body of federal common law that governed

interstate pollution. In the absence of such an explicit

command by Congress, this Court has no reason to

upset its precedents upholding field preemption

created by the constitutional structure.

From the beginning, this Court recognized that

the constitutional structure itself requires preemption

of certain fields. For example, in McCulloch

v. Maryland, 17 U.S. (4 Wheat.) 316 (1819), this Court

preempted state efforts to tax the national bank, a

federal instrumentality, even though no federal law

prohibited the tax. Chief Justice Marshall inferred

preemption from the constitutional structure because

otherwise states would “retard, impede, burden, or in

any manner control” federal policy. Id. at 436. Chief

Justice Marshall similarly held in Osborn v. Bank of

the United States, 22 U.S. (9 Wheat.) 738, 865 (1824),

that the Constitution preempted state efforts that

were “so objectionable” to federal operations and

rights. Neither the majority nor the dissent in Hencely

disagreed with this basic element of the constitutional

structure. Overturning precedent finding interstate

pollution to be a matter of federal common law would

deny the basic principles of federalism.

III.

Respondents Cannot Plead Any Valid

Tort Claims.

The Court should stop these state and local

attempts to set national climate policy through

frivolous state tort actions. In one breath, Boulder

asserts five traditional common law claims under

Colorado law: public nuisance, private nuisance,

trespass, unjust enrichment, and civil conspiracy.

J.A.112–23, J.A.127–36 (Am. Compl. ¶¶ 444–88, 501–

30). Specifically, Boulder seeks “past and future

damages” for its injuries caused by global “climate

change.” J.A.136 (Am. Compl. ¶ 532). It also seeks

“remediation” or “abatement of the hazards” of global

climate change “by any other practical means.”

J.A.138 (Am. Compl. ¶ 534). Yet, in the next breath it

insists that its claims do not purport “to impose

liability for activities that the [Clean Air Act]

regulates.” Pet.App.15a. Boulder’s “claims do not seek

compensation for any [greenhouse-gas emissions] by

[Petitioners] but direct their legal action solely to

Petitioners’

‘upstream

production

activities.’”

Pet.App.21a, none of which involves emissions. 4

4 A trial court in South Carolina saw such claims roughly the

same way: “For the reasons below, the Court grants Defendants’

motions and dismisses Plaintiff’s Complaint with prejudice. . . .

But even with the pleading sleight-of-hand, the

alleged facts cannot support a public nuisance claim.

Here, the errors of the decision below take at least two

forms. First, even as confined to physical injuries, tort

law does not allow individual injuries to be aggregated

into a public nuisance. See, e.g., Express Scripts, Inc.

v. Anne Arundel County, 353 A.3d 1084, 1133–34 (Md.

2026) (holding that licensed dispensing of a controlled

substance is not an actionable public nuisance,

Maryland common law never recognized a

government entity’s ability to recover damages for

public nuisance, and allegations regarding individual

injuries failed to sufficiently allege conduct affecting a

public right). That rule applies to the dissemination of

information to members of the public too. See State ex

rel. Hunter v. Johnson & Johnson, 499 P.3d 719, 726–

27 (Okla. 2021) (reversing a $465 million judgment

against a defendant for “creating a public nuisance in

the marketing and selling of its opioid products”

because the plaintiffs failed to establish that their

injuries came from an attack on a common right).

The rule applies here. The distribution of

information on the supposed harms from global

warming follows a unique path through many

different suppliers of information to many different

consumers. Respondents cannot pinpoint a single

damning statement from a sole source that reached all

[A]lthough Plaintiff’s claims purport to be about deception, they

are premised on, and seek redress for, the effects of greenhouse

gas emissions.” City of Charleston v. Brabham Oil Co., 2020-CP10-03975 (S.C. Ct. of Common Pleas Aug. 6, 2025), at 2.

drivers and other users of carbon-related products in

the same way at the same time. The required

“common interest” is just missing from this lawsuit.

Second, this error is compounded because

Respondents’ case flouts other requirements for a

public nuisance. Under § 822 of the Restatement

(Second) of Torts, a private nuisance holds an actor

“liable in an action for damages for a non-trespassory

invasion of another’s interest in the private use and

enjoyment

land.”

(emphasis

added).

Section 821B(1) of the Second Restatement defines a

public nuisance as “an unreasonable interference with

a right common to the general public.” (emphasis

added). And as just explained, the use of the word

“common” restricts the scope of these elements. Public

nuisance law has never included issues of

misrepresentation, concealment, or nondisclosure

rather than invasion or interference. The most

common invasions of public rights are blocking rights

of ways, Anonymous, Y.B. Mich., 27 Hen. 8, f. 27, pl.

10 (King’s Bench 1536), or discharging pollutants into

public waters, Burgess v. M/V Tamano, 370 F. Supp.

247 (D. Me. 1973). And the law has always “used the

same definition of nuisance to cover both public and

private nuisances,” with the former used to reach

damage to the public at large, instead of damages to

neighboring property owners. Richard A. Epstein, The

Private Law Connections to Public Nuisance Law:

Some

Realism

About

Today’s

Intellectual

Nominalism, 17 J.L. Econ. & Pol’y 282, 283 (2022).

Here, Respondents make sure to add the word

“invasion,” but simply to aver that Petitioners’ “fossil

fuel activities would cause and contribute to climate

change and thus cause these invasions of Plaintiff’s

property.” J.A.121 (Am. Compl. ¶ 475). Respondents,

however, never identify who committed these alleged

invasions; they never show that Petitioners released

or discharged any greenhouse gas onto Colorado’s

land, air, or waters. Instead, unidentified third-party

users of Petitioners’ products (which would have to

include Respondents themselves and their residents)

made the alleged “invasions.”

To fill this “nuisance” void, Respondents invent

a new claim that twists the law of misrepresentation.

The Supreme Court of Hawaii blessed the approach.

Hawaii, 537 P.3d at 1187. But Respondents pled

vague counts of fraudulent misrepresentation and

fraudulent concealment that fail to satisfy the

required elements of even these misrepresentation

torts. Once the verbal surplusage is stripped away, all

that remains is a bare assertion that Petitioners sold

lawful products in a lawful manner.

Despite settled law, the proceedings below are

replete with references to alleged misrepresentations

and concealment. But misrepresentation and

concealment claims must start with the proposition

that the defendant has possession of material

information that is not known to the plaintiff, after

which the defendant makes a false statement to the

plaintiff or omits to mention a relevant material fact.

The plaintiff must, to its detriment, then rely on the

false statement or improper omission to its detriment.

The Restatement explains:

One who fraudulently makes a

misrepresentation of fact, opinion,

intention or law for the purpose of

inducing another to act or to refrain

from acting, is subject to liability for

economic loss caused by the other’s

justifiable

reliance

the

misrepresentation.

See Restatement (Third) of Torts: Liability for

Economic Harm § 9.

Here, Respondents fail each required element.

They do not name the full class of proper defendants,

they do not explain causation, and they do not explain

their justifiable reliance.

A trial court judge in Baltimore recently

characterized the identical failures of a similar

lawsuit:

Baltimore seeks compensatory and

punitive damages, disgorgement of

profits, civil penalties under the

MCPA, and equitable relief. . . . [But

t]he explanation by Baltimore that it

only seeks to address and hold

Defendants accountable for a deceptive

misinformation campaign is simply a

way to get in the back door what they

cannot get in the front door.

Mayor & City Council of Baltimore v. B.P. P.L.C., 24C-15-004219 (Circuit Ct. for Baltimore City July 10,

2024), at p. 11 (emphasis added). The Maryland

Supreme Court affirmed that trial court’s observation.

Mayor & City Council of Baltimore v. B.P. P.L.C., 353

A.3d 1142 (Md. 2026). The trial court’s point in the

Maryland case is obviously correct. Courts cannot

allow Respondents to manipulate state tort laws of

misrepresentation and nuisance to get from

Petitioners the same damages as they could if they

were the actual polluters—all while denying that

their case has anything to do with actual pollution.

Narrowing the review from the big picture to closer

scrutiny of these three elements further reveals

Respondents’ inability to plead their claims:

A. Respondents have failed to identify a

proper defendant.

Respondents single out large energy companies

as defendants. But they do not explain why they

picked these two firms from the many energy

producers worldwide or the many dealers and

retailers of fossil fuel products in Colorado. They do

not name any false statement made by Petitioners to

Colorado drivers or other residents about fossil fuels

and climate change. They do not even explain that any

misstatements or substantive omissions reached

Boulder residents within the relevant time.

Nor is this a case of concealment in the absence

of a duty to disclose. The promotion of oil and gas, for

example, does not resemble the specific health claims

that tobacco companies made about their products.

Their charges do not say that Petitioners told the

public—through advertisements—about anything

other than price, mileage, additives, and services.

Sellers, distributors, and consumers manage,

use, consume, and promote fossil fuel products in

countless goods and services sold or delivered within

Colorado without mentioning carbon dioxide or global

warming. On Respondents’ theory, the list of other

defendants must go far beyond the sellers of fossil fuel

products to include the sellers of cars, trucks, and

airplanes in Colorado, and the many companies that

supply natural gas and coal products to Colorado

residents. Respondents continue to use fossil fuels in

their own operations, and they have unlimited access

to vast amounts of information on what they consider

to be the scope and importance of global warming. Yet

no individual Respondent in this case sued the state

or county, or even reduced their own claims to reflect

their own culpability on the very theory they impose

on Petitioners.

The critical role of third-party suppliers is also

ignored. Under joint and several liability, Petitioners’

alleged misrepresentations amount to at most a tiny

fraction of those made by the thousands of firms

whose activities involve fossil fuels. Under the two

prevailing rules for apportioning loss, § 433A of the

Restatement (Second) Torts and the Comprehensive

Environmental Response, Compensation, and

Liability Act, 42 U.S.C. § 9613(f), there must be a

reasonable basis for division, for example here by

market share, for any fraction of alleged

misrepresentations made. Petitioners’ supposed

contributions would be de minimis.

B. There is no materiality or causation.

In every tort case, a plaintiff must show that

the actions attributed to the defendant have caused

the specified harm. The complaint here fails to do

that. Therefore, Respondents must prove causation by

showing that the alleged misrepresentations satisfy

two conditions.

First, they must show that if the requisite

misstatements or omissions had not taken place,

there would have been a lower level of consumption of

fossil fuels. Second, they must show that without the

increases in fuel-consumption levels, the alleged local

adverse events would have been reduced or even

eliminated.

As to the first condition, Respondents cannot

maintain their claims because they and the public at

large knew as much or more about global warming as

Petitioners. Respondents do not even allege that

Petitioners’ statements produced increases in fuelconsumption levels. At most, Respondents allege that

Petitioners’ supposed misrepresentations caused

increases “in extreme hot summer days and increases

in minimum nighttime temperatures, precipitation

changes, larger and more frequent wildfires,

increased concentrations of ground-level ozone,

higher transmission of viruses and disease from

insects, altered streamflows, bark beetle outbreaks,

ecosystem damage, forest die-off reduced snowpack,

and drought.” J.A.39 (Am. Compl. ¶ 140).

Nor can Respondents satisfy their pleading

burden on tort claims by simply claiming vague

adverse climate effects from temperature increases,

as if this were a poorly pled res ipsa loquitur case.

Moving back one link mightily increases the length of

the causal chain. To succeed, Respondents must allege

at a minimum that increased consumption of fossil

fuels attributable to nonspecific representations by

these Petitioners were both material and sufficient to

produce changes in consumption levels that could in

turn lead to higher levels of emissions. Then they

must allege that these supposed increases in

emissions would have produced the necessary

temperature changes to cause the alleged adverse

climate events. Respondents cannot claim that the

consequences of all weather-related changes must be

laid on Petitioners’ doorsteps because of their general

marketing activities.

Respondents’ causal chain is composed of

missing links. It ignores the sequence of events that

would theoretically link Petitioners’ conduct to the

possible damages, given that Petitioners’ fossil fuel

sales also include coal, natural gas, and gasoline.

These different energy sources are distributed

through different channels. Coal is often sold to

industrial users; natural gas is used for heating and

industrial purposes; gasoline is commonly sold at

automobile service stations. Respondents do not

identify the different improper communications that

accompany each distinct method of distribution, and

they cannot show that the supposed forms of

misinformation were material and sole sources of

greenhouse

gases

information

whatever

hypothetical groups of buyers.

Take, for example, the sale of gasoline at

service stations. If Petitioners had revealed all

allegedly true information about global warming,

Respondents do not explain what difference it would

make in the driving patterns of individual drivers, all

of whom have been bombarded with identical claims

about the dangers of greenhouse gases for years on

end. Consumers might believe that reducing their

individual gasoline consumption might have only an

infinitesimal effect on global warming. They would

then have to balance this microscopic harm (if it is

harm at all) against the major changes in lifestyle that

would occur if they could not drive to work or take

their kids to school.

Those sacrifices would loom too large for

individuals willingly to change major driving habits.

Consumers and consumption levels are far more

responsive to taxes and regulations that immediately

affect prices. Changes in consumer behavior due to

federal regulation of fossil fuels swamp any weak

voluntary responses to the repetition of familiar

charges about the dangers of greenhouse gases.

What’s more, the disparate modes of production and

distribution for coal and natural gas are also subject

to comprehensive regulation. The Express Scripts

court, 353 A.3d at 1131–1134, offered powerful

reasons for judges to stay their hands in fashioning

common law remedies in already heavily regulated

areas like environmental law. After all, “Litigation

should not be used to achieve legislative goals.” City

of Chicago v. Beretta U.S.A. Corp., 821 N.E.2d 1099,

1123 (Ill. 2004). Respondents would prefer that the

Nation make different decisions about climate and

energy policy, but expanding tort law by allowing this

case to go forward is not the way to get there.

In sum on this point, it is implausible that any

communications by Petitioners about their products

would have influenced levels of consumption. The

increasing demand for Petitioners’ products in

Colorado and worldwide has a far greater impact on

consumption than anything Petitioners supposedly

said or did. The theory that global consequences

attach to both local sales campaigns and to the alleged

nondisclosure of research activities over the last fifty

or more years creates an open ticket to collect tens of

billions of dollars, not only in Boulder, but also

worldwide. Yet each allegation of an adverse event

claimed to arise from misrepresentation during fossil

fuel sales is both speculative and unsustainable.

The claims of irreversible damage require a

detailed and separate account of each element in the

chain of causation. See Ashcroft v. Iqbal, 556 U.S. 662

(2009); Bell Atlantic, Corp. v. Twombly, 550 U.S. 544

(2007). Respondents failed to explain the direct link

between Petitioners’ supposed statements or nonstatements, which may or may not have accompanied

the sales of their products, to the asserted physical

damages. They cannot carry their pleading burden if

they cannot rule out other well-known causes—poor

forest management etc.—that bring about the same

alleged harms produced by greenhouse gas emissions.

C. Respondents cannot show any basis

for justifiable reliance.

American law distinguishes between speaking

falsely to someone and actively deceiving someone. It

is not possible to deceive a person who knows the true

facts, because that knowledge precludes any

justifiable reliance on the defendant’s statements or

omissions.

Here, Respondents did not identify anyone who

could show actual reliance on Petitioners’ supposed

misrepresentations. They had to identify a

misrepresentation or concealment by Petitioners that

fossil fuels “do no harm to the environment.” They

offered no explanation why these defendants, among

thousands of other possible parties, including

Respondents themselves, had this supposed unique

duty of disclosure to the public.

But even if every statement uttered by

Petitioners were false, Respondents could still not

justifiably rely on the supposed statements about

climate change. Hundreds, if not thousands, of

sources proclaim the threat that greenhouse gases

pose to the environment. Respondents cannot claim

that these defendants withheld critical information

about the effects of greenhouse gases. Whether

correctly or not, intensive public knowledge and

discussion of these issues already exist. For example,

the United Nations’ Intergovernmental Panel on

Climate Change issued a 2021 report in a press release:

“Climate change is widespread, rapid, and

intensifying, and some trends are now irreversible, at

least during the present time frame.” 5 In the same

press release, UN Secretary-General António

Guterres declared that the IPCC’s Working Group’s

report was nothing less than “a code red for

humanity.” “The alarm bells are deafening, and the

evidence is irrefutable.” Guterres called publicly for a

fossil fuel ban to avoid “an escalating crisis.”

Websites such as Carbon Monitor 6 give

exhaustive updates on all-issues carbon. Just

recently, James Gustave Speth published a book, They

5 United Nations, IPCC report: ‘Code red’ for human driven

global heating, warns UN chief (Aug. 9, 2021),

https://news.un.org/en/story/2021/08/1097362, last visited July

9, 2025.

6 https://carbonmonitor.org/, last visited July 9, 2025.

Knew. 7 Who is “they”? It is not Petitioners, but rather,

as the subtitle says, it is “The US Federal

Government’s Fifty-Year Role in Causing the Climate

Crisis.”

One can agree or disagree with any of these

studies, but what Respondents cannot show or even

allege is that in all this “information”—some good,

some bad—Petitioners’ supposed silence has led to

changes in fossil fuel consumption, let alone to

changes in temperature. Public statements from a

multitude of public and private sources make it

impossible to conceive of Petitioners as playing a

significant role, let alone a decisive one, in the public

creation and transmission of carbon-related

information. Respondents cannot sufficiently allege

that Petitioners by some devious schemes were able to

keep the public in the dark.

How can there be reliance? The law of fraud

rests on the rule that a defendant cannot keep private

information secret in its commercial dealings with

others. The minimum condition to prove a fraud case

is asymmetric information between the two parties.

The defendants must know something that the

plaintiffs do not. A leading illustration is the English

case, Derry v. Peek, L. R. 14 App. Cas. 337 (1889).

There, the fatal misrepresentation was that

defendants had “the right to use steam or mechanical

motive power instead of horses” to run their trams

7 https://mitpress.mit.edu/9780262545099/they-knew/, last

visited July 9, 2025.

along the public way, even though they had secured

such authorization for only part of that way. Id. at

347. The concealment of that vital information hurt

the plaintiffs’ investment prospects. The plaintiffs,

who had no independent source of information, relied

on the defendants. This case raises the opposite

prospect. It bears similarity to the situation

condemned nearly 100 years ago by Justice Benjamin

Cardozo, in a case involving financial fraud

undetected by accountants, against imposing “a

liability in an indeterminate amount for an

indeterminate time to an indeterminate class.”

Ultramares Corp. v. Touche, 174 N.E. 441, 444 (N.Y.

1931).

Here, Respondents have filed only generic

allegations that anyone could repeat virtually

verbatim, with a few name changes, against a broad

universe of defendants. Every producer, user, and

consumer of fossil fuels, and every entity in the supply

chain in between, could become the next defendant in

a suit for contributing to energy use, which allegedly

increases greenhouse gases, allegedly raises global

temperatures, and then allegedly causes climate

change, which may harm Colorado somewhere, maybe

including Boulder County—along with every other

state in the Union. Hundreds of cities and counties

could bring copycat complaints that could plunge

these defendants, or any of a thousand other firms,

into the same morass. The Court should reverse the

decisions below and should reject such limitless

theories of tort liability.

♦

CONCLUSION

For these reasons, the Court should reverse the

decisions below.

Respectfully submitted,