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

Supreme Court briefAug 3, 2026

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No. 25-170

IN THE

Supreme Court of the United States

————

SUNCOR ENERGY (U.S.A.) INC.; SUNCOR ENERGY

SALES INC.; EXXON MOBIL CORPORATION,

Petitioners,

COUNTY COMMISSIONERS OF BOULDER COUNTY;

CITY OF BOULDER,

Respondents.

————

On Writ of Certiorari to the

Supreme Court of Colorado

————

BRIEF OF THE HON. SCOTT A. SUROVELL,

VIRGINIA SENATE MAJORITY LEADER, AND

SENATOR R. CREIGH DEEDS, DELEGATE

KATRINA E. CALLSEN, AND DELEGATE AMY

J. LAUFER, MEMBERS OF THE VIRGINIA

GENERAL ASSEMBLY, AS AMICI CURIAE

IN SUPPORT OF RESPONDENTS

————

CALE JAFFE

Counsel of Record

DIRECTOR, ENVIRONMENTAL LAW AND

COMMUNITY ENGAGEMENT CLINIC

UNIVERSITY OF VIRGINIA SCHOOL OF LAW

580 Massie Road

Charlottesville, VA 22903

(434) 924-4776

cjaffe@law.virginia.edu

Counsel for Amici Curiae

WILSON-EPES PRINTING CO., INC. – (202) 789-0096 – WASHINGTON, D.C. 20002

TABLE OF CONTENTS

Page

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

iii

AMICI CURIAE, MEMBERS OF THE

VIRGINIA GENERAL ASSEMBLY................

STATEMENT OF INTEREST OF AMICI..........

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

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

I. Virginia Uranium calls for deference to

Colorado’s historic police powers in

managing its courts ..................................

II. Petitioners’ “causal chain” theory of preemption would invalidate broad swaths

of uncontested state authority in Virginia

and every other state in the union. ..........

III. The cooperative federalism structure of

the Clean Air Act works to block

Petitioners’ broad overreach into areas of

traditional state control. ...........................

IV. The presumption against preemption is

necessary to protect states’ sovereignty...

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

(i)

TABLE OF AUTHORITIES

CASES

Page(s)

Arizona v. United States,

567 U.S. 387 (2012) ...................................

Bates v. Dow Agrosciences LLC,

544 U.S. 431 (2005) ...................................

Cipollone v. Liggett Group, Inc.,

505 U.S. 504 (1992) ................................... 3, 19

Commonwealth of Virginia v. Browner,

80 F.3d 869 (4th Cir. 1996), cert. denied

519 U.S. 1090 (1997) .................................

Energy & Environment Legal Institute

v. Epel,

793 F.3d 1169 (10th Cir. 2015) .................

Georgia v. Tennessee Copper Co.,

206 U.S. 230 (1907) ......................... 2, 13, 14, 21

Gregory v. Ashcroft,

501 U.S. 452 (1991) ...................................

Held v. Montana,

580 P.3d 1235 (Mont. 2024) ...................... 19, 20

Hencely v. Fluor Corp.,

608 U.S. ___, 146 S. Ct. 1086 (2026) ........ 20, 21

International Paper Co. v. Ouellette,

479 U.S. 481 (1987) ...................................

Massachusetts v. EPA,

549 U.S. 497 (2007) ............................... 7, 16, 17

Medtronic, Inc. v. Lohr,

518 U.S. 470 (1996) ...................................

iii

TABLE OF AUTHORITIES—Continued

Page(s)

Monsanto v. Durnell,

609 U.S. ___, No. 24-1068, slip op.

(June 25, 2026) ..........................................

Pacific Gas & Elec. Co. v. State Energy

Res. Conservation & Dev. Comm’n,

461 U.S. 190 (1983) ...................................

4-6

Puerto Rico Dep’t of Consumer Affairs. v.

Isla Petroleum Corp.,

485 U.S. 495 (1988) ................................... 8, 18

Rice v. Santa Fe Elevator Corp.,

331 U.S. 218 (1947) ................................... 4, 17

Seven County Infrastructure Coalition. v.

Eagle County, Colorado,

605 U.S. 168 (2025) ...................................

Shady Grove Orthopedic Assocs., P.A. v.

Allstate Ins. Co.,

559 U.S. 393 (2010) ...................................

Silkwood v. Kerr-McGee Corp.,

464 U.S. 238 (1984) ...................................

United States v. O’Brien,

391 U.S. 367 (1968) ...................................

United States Forest Service v. Cowpasture

River Preservation Association,

590 U.S. 604 (2020) ...................................

Virginia Uranium v. Warren, Inc.,

587 U.S. 761 (2019) .................................. 2-8, 21

Wyeth v. Levine,

555 U.S. 555 (2009) ...................................

TABLE OF AUTHORITIES—Continued

CONSTITUTION

Page(s)

U.S. Const. art. VI, § cl. 2......................... 3, 19, 20

STATUTES

42 U.S.C. § 7401, et seq. ...............................

§ 7401(a)(3)................................................

§ 7604 ........................................................

§ 7416 ........................................................

Air Pollution Control Act of 1955, Pub. L.

159, 69 Stat. 322 (July 14, 1955) ..............

Clean Air Act of 1963, Pub. L. 88-206, 77

Stat. 396 (Dec. 17, 1963) ...........................

Federal Insecticide, Fungicide, and

Rodenticide Act, 7 U.S.C. § 136v(b) .........

2026 Va. Acts ch. 07, § 1-16 R of Item 365 ..

Va. Code § 10.1-1183(B)(2) ...........................

Va. Code § 15.2-958.3 ...................................

Va. Code § 33.2-501 ......................................

Va. Code § 45.2-1706.1(A) ............................

Va. Code § 46.2-870 ......................................

Va. Code § 54.1-1134 ....................................

Va. Code § 56-585.5(E) ................................. 10, 11

Va. Code § 56-596.2 ......................................

Va. Code § 58.1 2217 ....................................

Virginia Clean Economy Act, 2020 Va. Act.

ch. 1193, ch. 1194 ......................................

TABLE OF AUTHORITIES—Continued

Page(s)

REGULATIONS

Final Rule, EPA, Recission of the

Greenhouse Gas Endangerment Finding

and Motor Vehicle Greenhouse Gas

Emission Standards under the Clean Air

Act, 91 Fed. Reg. 7686 (Feb. 18, 2026) ..... 7, 16

STATUTORY BACKGROUND

National Air Quality Standards Act of

1970, Report of the Committee on Public

Works, United States Senate, S. Rep. 911196 (Sept. 17, 1970) ................................ 3, 15

OTHER AUTHORITIES

Arnold W. Reitze, Jr., A Century of Air

Pollution Control Law: What’s Worked;

What’s Failed; What Might Work, 21

Envtl. L. 1549 (1991) ................................

Caleb E. Nelson, Preemption, 86 Va. L. Rev.

225 (2000) .................................................. 3, 20

Center for Climate & Energy Solutions,

State Greenhouse Gas Emissions Targets,

https://www.c2es.org/document/greenho

use-gas-emissions-targets/ (last updated

Aug. 2025) .................................................

TABLE OF AUTHORITIES—Continued

Page(s)

Comments of the American Petroleum

Institute on the Proposed Rule Entitled

“Reconsideration of 2009 Endangerment

Finding and Greenhouse Gas Vehicle

Standards,” Docket ID No. EPA-HQOAR-2025-0194 (submitted Sep 22,

2025), https://www.regulations.gov/com

ment/EPA-HQ-OAR-2025-0194-0869.......

The Federalist No. 32 (Alexander

Hamilton) (Clinton Rossiter ed., 1961) ....

Jonathan

Adler,

Displacement

and

Preemption of Climate Nuisance Claims,

17 J. L. Econ. & Pol’y 217 (2022)..............

Michael P. Vandenbergh, From Smokestack

to SUV: The Individual as Regulated

Entity in the New Era of Environmental

Law, 57 Vand. L. Rev. 515 (2004) ............

National Research Council, Uranium

Mining in Virginia: Scientific, Technical,

Environment-al, Human Health and

Safety, and Regulatory Aspects of

Uranium Mining and Processing in

Virginia (The National Academies Press

2012),

https://www.nationalacademies

.org/projects/DELS-BESR-09-06 ..............

Pace Equity Finance, States with Active CPACE Financing, https://www.paceequity.com/c-pace-states/ (last visited

July 23, 2026) ............................................

vii

TABLE OF AUTHORITIES—Continued

Page(s)

RGGI, Elements of RGGI, https://www.rggi.

org/program-overview-and-design/elements

(last visited July 29, 2026) .......................

RGGI, Regional Greenhouse Gas Initiative:

Memorandum of Understanding, https://

www.rggi.org/sites/default/files/Uploads/

Design-Archive/MOU/MOU_12_20_05.

pdf (Dec. 20, 2005) ....................................

Tax Foundation, Gas Taxes by State, 2025,

https://taxfoundation.org/data/all/state/g

as-taxes-state/ (Sept. 2, 2025). .................

AMICI CURIAE, 1 MEMBERS OF

THE VIRGINIA GENERAL ASSEMBLY

State Senator Scott A. Surovell is the Senate

Majority Leader and represents the 11th Senatorial

District in Virginia, covering part of Fairfax County.

He is also Chair of the Virginia Senate Committee on

Courts of Justice, and serves on Committees for

Commerce and Labor, Finance and Appropriations,

Rehabilitation and Social Services, and Rules.

State Senator R. Creigh Deeds represents the 11th

Senatorial District in Virginia, covering all of

Albemarle County, Amherst County, Nelson County

and the City of Charlottesville, and part of Louisa

County. He is Chair of the Virginia Senate Committee

on Commerce and Labor, and serves on Committees

for Courts of Justice, Finance and Appropriations,

Privileges and Elections, and Rules.

Delegate Katrina E. Callsen represents the 54th

House District in Virginia, covering part of Albemarle

County and all of the City of Charlottesville. She

serves on the Virginia House Committee on Finance,

as well as on Committees for Courts of Justice,

Privileges and Elections, and General Laws.

Delegate Amy J. Laufer represents the 55th House

District, covering parts of Albemarle County, Fluvanna County, Louisa County, and Nelson County. She

serves on the Virginia House Committee on Agriculture, Chesapeake and Natural Resources, as well

as on Committees for Education and Appropriations.

Pursuant to Rule 37.6, counsel for amici curiae certifies that

no person or entity other than amici curiae and their counsel

authored this brief in whole or in part. No person other than

amici curiae and their counsel made a monetary contribution to

its preparation or submission of the brief.

STATEMENT OF INTEREST OF AMICI

Amici curiae are members of the Virginia General

Assembly with a strong interest in preserving the

constitutional balance that protects the states’ historic

role in remediating local harms through traditional

tort law. Amici are submitting this brief to respectfully

urge the Court to affirm the Colorado Supreme Court’s

decision and uphold the vital role for states in helping

their residents seek recovery for injuries associated

with climate change. Whether Respondents are able to

secure recovery for these harms is ultimately a

question for Colorado judges and juries to consider.

Amici curiae’s perspective is shaped, in part, by

their experience as legislators in a state that endured

a remarkably similar preemption challenge to the one

that Colorado and its municipalities face today. In

Virginia Uranium v. Warren, Inc., 587 U.S. 761 (2019),

the Court upheld the Commonwealth of Virginia’s

state-level ban on uranium mining on private land—

even as the federal Atomic Energy Act pervasively

covered the processing of mined uranium ore into

nuclear fuel. Upstream impacts on federally regulated

activities did not derail Virginia’s authority. Id. at 765.

SUMMARY OF ARGUMENT

This Court should uphold Colorado’s plenary authority to open its state courthouse doors to consider

claims of public nuisance, private nuisance, trespass,

unjust enrichment, civil conspiracy, and violations of

the Colorado Consumer Protection Act—notwithstanding upstream impacts on the production of

greenhouse gas-emitting fuels.

1. The lead and concurring opinions in Virginia

Uranium provide a controlling framework: federal

courts should not assume preemption simply because

a state law has an ancillary effect on upstream

activities related to a federal regulatory regime. 587

U.S. at 770-71, 790-91.

2. Conflicting with Virginia Uranium and other

precedents, Petitioners’ propose a “causal chain” test

for implied preemption that risks invalidating broad

swaths of uncontested state authority, from state

Renewable Portfolio Standards to gas taxes. See infra

pp. 9-14.

3. Petitioners’ theory also contradicts Congress’s

clear intention in framing the Clean Air Act to

preserve state tort remedies: “Compliance with standards under this Act would not be a defense to a

common law action for pollution damages.” National

Air Quality Standards Act of 1970, Report of the

Committee on Public Works, United States Senate, S.

Rep. 91-1196, at 38 (Sept. 17, 1970).

4. Finally, legal scholarship on preemption further

confirms why application of Virginia Uranium is

necessary here to preserve vital roles for state law and

state courts. See, e.g., Caleb E. Nelson, Preemption, 86

Va. L. Rev. 225–305, 231–32 (2000) (“Under the

Supremacy Clause, preemption occurs if and only if

state law contradicts a valid rule established by

federal law, and the mere fact that federal law serves

certain purposes does not automatically mean that it

contradicts everything that might get in the way of

those purposes”).

ARGUMENT

I. Virginia Uranium calls for deference to

Colorado’s historic police powers in

managing its courts.

Respondents’ Colorado lawsuit has as much of an

impact on greenhouse gas emission standards as a

speeding ticket has on tailpipe pollution regulations.

Issuing a fine to a motorist and directing him to drive

more slowly will have the upstream benefit of reducing

fuel consumption. But no one would label a traffic

citation as an emissions regulation. By the same

token, Respondents’ state-law claims for climate-related injuries are not in conflict with any federal

regulation under the Clean Air Act (CAA), 42 U.S.C.

§ 7401, et seq., because these claims do not seek to

regulate greenhouse gas emissions nor do they conflict

with any emissions limit that EPA might set. See, e.g.,

Cipollone v. Liggett Group, Inc., 505 U.S. 504, 528–29

(1992) (opinion of Stevens, J.) (“fraudulent-misrepresentation claims … are not pre-empted … Such

claims are predicated not on a duty ‘based on smoking

and health’ but rather on a more general obligation—

the duty not to deceive.”) (cleaned up).

As legislators from a state that withstood a similar

preemption challenge to the one Colorado now faces,

amici curiae know all too well the risks that “some

brooding federal interest or appeal[] to a judicial

policy preference” can pose to a state’s legitimate

exercise of its plenary authority. Virginia Uranium,

587 U.S. at 767.

Justice Gorsuch’s lead opinion in Virginia Uranium

confirmed that preemption must be grounded in “the

text and structure of the statute.” 587 U.S. at 778

(internal citation omitted). Courts “‘start with the

assumption that the historic police powers of the

States were not to be superseded by the Federal Act

unless that was the clear and manifest purpose of

Congress.’” Medtronic, Inc. v. Lohr, 518 U.S. 470, 485

(1996) (quoting Rice v. Santa Fe Elevator Corp., 331

U.S. 218, 230 (1947)). The contrary approach claimed

by Petitioners would impose a “sweeping interpretation” of federal preemption and “would require far

greater interference with state legal remedies, producing a serious intrusion into state sovereignty….”

Medtronic, 518 U.S. at 488-89.

A deferential standard is especially vital in areas of

law where history and tradition favor regulation by

the states. See Pacific Gas & Elec. Co. v. State Energy

Res. Conservation & Dev. Comm’n, 461 U.S. 190, 194

(1983) (rejecting a preemption challenge aimed at

“historic state authority over the generation and sale

of electricity”). Alexander Hamilton’s early explanation on the “rights of sovereignty” retained by the

states is instructive. Under the Constitution, he presumed, “this alienation of state sovereignty, would only

exist in three cases: where the constitution in express

terms granted an exclusive authority to the Union;

where it granted in one instance an authority to the

union, and in another prohibited the states from

exercising the like authority; and where it granted an

authority to the Union to which a similar authority

in the states would be absolutely and totally

contradictory and repugnant.” The Federalist No. 32,

at 198 (Alexander Hamilton) (Clinton Rossiter ed.,

1961) (emphasis in original). Stated more colloquially,

the rule is this: in baseball, a tie goes to the runner; in

preemption jurisprudence, it goes to the states.

Deference to state government authority also

means, as Justice Gorsuch articulated, that courts

must look to “what the State did, not why it did

it.” Virginia Uranium, 587 U.S. at 774 (emphasis in

original) (referencing Arizona v. United States, 567

U.S. 387 (2012)). In a complimentary vein, Justice

Ginsburg’s concurrence in Virginia Uranium expressly rejects the argument that a state law could be

“preempted because it is a pretext for regulating”

another field that Congress had delegated to a federal

agency. Virginia Uranium, 587 U.S. at 789.

The lead and concurring opinions in Virginia

Uranium likewise build upon this Court’s ruling in

Pacific Gas, which cautions that “inquiry into legislative motive is often an unsatisfactory venture” because “[w]hat motivates one legislator to vote for a

statute is not necessarily what motivates scores of

others to enact it.” 461 U.S. at 216. (citing United

States v. O’Brien, 391 U.S. 367, 383 (1968)). See also

Shady Grove Orthopedic Assocs., P.A. v. Allstate Ins.

Co., 559 U.S. 393, 404 (2010) (the “approach of

determining whether state and federal rules conflict

based on the subjective intentions of the state legislature is an enterprise destined to produce ‘confusion

worse confounded’”) (internal citation omitted).

To be sure, the Virginia Uranium dissenters worried that courts might wish to inquire into a state’s

legislative purposes to determine whether a state’s

action over a non-preempted field was being leveraged

as a backdoor means of blocking an unpopular federal

law. 587 U.S. at 797 (Roberts, C.J., dissenting)

(citing Pacific Gas, 461 U.S. at 212-213). Yet that concern is not present here for the obvious reason that the

only motives at issue are those of Respondents acting

as non-state litigants. Their motivations cannot be

ascribed to the legislature or state courts of Colorado.

The state’s only action has been to open the courthouse

doors.

***

It is noteworthy that Petitioners’ claims regarding

implied preemption are far weaker than the failed

claims considered in Virginia Uranium. There, a

mining company had challenged Virginia’s outright

ban on an entire class of state-regulated activity

(uranium mining), which was acknowledged to be a

necessary predicate to a federally regulated activity

(uranium milling and processing). There had been no

in-state processing of uranium ore since 1982, i.e.,

since the Commonwealth’s ban on mining had been

enacted. See National Research Council, Uranium

Mining in Virginia: Scientific, Technical, Environmental, Human Health and Safety, and Regulatory

Aspects of Uranium Mining and Processing in Virginia

at 7 (The National Academies Press 2012), https://

www.nationalacademies.org/projects/DELS-BESR-0906. Yet those facts did not sway the Court to

intervene—because Congress had not intervened. The

Court would “not expose every state law on every

subject to a searching judicial inquiry into its latent

purposes.” Virginia Uranium, 587 U.S. at 770.

In contrast, nothing about the City and County of

Boulder’s state-law claims purport to ban the production of fossil fuels. Nor is there any indication

that Petitioners will be barred from continuing with

any federally regulated activities. On the contrary,

Respondents are merely seeking compensation for

state-level injuries that are attributable to an upstream activity that the federal government is

(unlawfully) declining to regulate. See Final Rule,

EPA, Recission of the Greenhouse Gas Endangerment

Finding and Motor Vehicle Greenhouse Gas Emission

Standards under the Clean Air Act, 91 Fed. Reg. 7686

(Feb. 18, 2026); cf. Massachusetts v. EPA, 549 U.S.

497, 532–33 (2007). (“EPA’s decision … rests on

reasoning divorced from the statutory text.”)

***

Virginia Uranium serves as a North Star, articulating a foundational feature of preemption jurisprudence: “Consider just some of the costs to cooperative federalism and individual liberty we would

invite by inquiring into state legislative purpose too

precipitately.… That would inhibit the sort of open

and vigorous legislative debate that our Constitution

recognizes as vital to testing ideas and improving

laws.” 587 U.S. at 775 (lead opinion); id. at 790–91

(Ginsburg, J., concurring) (“A state law regulating an

upstream activity within the State’s authority is not

preempted simply because a downstream activity falls

within a federally occupied field.”).

If Petitioners wish to preempt Respondents’ claims,

they “must point specifically to ‘a constitutional text or

a federal statute’ that” explicitly requires such a

result. Id. at 767 (internal citation omitted) (quoting

ISLA Petroleum, 485 U.S., at 495, 503). Yet amici

curiae in support of Petitioners acknowledge that no

such text exists. Br. of Alabama, et al., in Support of

Pet’rs, at 25 (filed May, 21, 2026) (“One does not need

‘text’”). This apparent concession should be fatal to

Petitioners’ claims of implied preemption. Virginia

Uranium, 587 U.S. at 778 (lead opinion) (“only federal

laws ‘made in pursuance of’ the Constitution, through

its prescribed processes of bicameralism and presentment, are entitled to preemptive effect.”).

Just as Virginians were able to make their own

state-law decisions on whether to maintain a moratorium on uranium mining, Coloradans should now

be afforded the freedom to adjudicate claims seeking

recovery for their acute, localized, climate changerelated injuries.

II. Petitioners’ “causal chain” theory of preemption would invalidate broad swaths of

uncontested state authority in Virginia

and every other state in the union.

Petitioners’ chief error—failing to account for

Virginia Uranium and its guidance on preemption—is

compounded by their overbroad “causal chain” theory

of field preemption, which is wildly overinclusive and

would dramatically undercut state sovereignty. Petitioners frame their test as follows:

“In particular, to prove the element of causation for its tort claims, respondents must

show that, absent petitioners’ production and

marketing of their products, fewer fossil fuels

would have been used …. Interstate emissions are thus a critical step in the causal

chain between petitioners’ alleged conduct

and respondents alleged injuries.”

Br. for Pet’rs, at 35-36 (emphasis added). This “causal

chain” theory of preemption is not just overbroad—it

is nonsensical.

Accepted on its own terms, Petitioners’ test would

render unlawful any state-law action whose mechanism or purpose has the effect of reducing greenhouse

gas pollution from fossil fuels. 2 Such an approach

The production of fossil fuels, like so much economic activity,

has an upstream impact on interstate interests. Yet this Court

has already declined to hinge federal authority (in another

context) based on upstream impacts on oil drilling and

downstream impacts on oil refining, finding such connections far

too attenuated. Seven County Infrastructure Coalition. v. Eagle

County, Colorado, 605 U.S. 168, 179 (2025).

would invalidate broad swaths of uncontested state

authority—to impose gas taxes, require efficiency

standards through building codes, or promote renewable energy development via state public utility

commissions—because these actions have upstream

impacts on interstate, greenhouse gas emissions.

Virginia has joined nearly half of her sister states in

enacting laws aimed at the vital task of decarbonization, with an ancillary, upstream impact on

greenhouse gas emissions. See Center for Climate &

Energy Solutions, State Greenhouse Gas Emissions

Targets, https://www.c2es.org/document/greenhousegas-emissions-targets/ (last updated Aug. 2025) (calculating that “22 states and the District of Columbia

have established economy-wide greenhouse gas

emissions targets”).

Virginia, for example, recently rejoined the Regional

Greenhouse Gas Initiative (RGGI), and is managing

its reentry to the program, in part, through historic

state-law powers over electric utilities. See 2026 Va.

Acts ch. 07, § 1-16 R of Item 365. RGGI is premised on

reducing greenhouse gas emissions across its member

states, with those emissions possibly serving as “a

critical step in the causal chain,” Br. for Pet’rs, at 36,

between obligations imposed on electric utilities and

state laws imposing those obligations. Yet for more

than two decades, RGGI has existed without any

intrusion whatsoever into EPA’s authority under the

Clean Air Act. See RGGI, Regional Greenhouse Gas

Initiative: Memorandum of Understanding, https://w

ww.rggi.org/sites/default/files/Uploads/Design-Archiv

e/MOU/MOU_12_20_05.pdf at 2 (Dec. 20, 2005) (announcing a program “aimed at stabilizing and then

reducing CO2 emissions within the Signatory States”

and signed by three Republican governors and four

Democrats). 3

RGGI is not the only climate change-oriented initiative under Virginia law. The Commonwealth’s Renewable Portfolio Standard (RPS) program sets

accelerating targets for the “[g]eneration of electricity

from renewable and zero carbon sources.” Va. Code

§ 56-585.5. The state’s energy efficiency mandate

similarly requires power companies to meet annual

electricity savings goals. Va. Code § 56-596.2. And

utilities must also increase development of energy

storage (i.e., battery) technologies to reduce reliance

on backup, fossil-fuel generation. Va. Code § 56585.5(E). All of these programs were enacted as part

of the Virginia Clean Economy Act, 2020 Va. Act. ch.

1193, ch. 1194.

The list of Virginia’s greenhouse gas-adjacent initiatives continues to the Commonwealth’s “Clean

Energy Policy,” which affirms “that addressing

climate change requires reducing greenhouse gas emissions across … all sectors, including the electric power, transportation, industrial, agricultural, building,

and infrastructure sectors.” Va. Code § 45.2-1706.1(A).

The Virginia Department of Environmental Quality is

further directed to “address climate change by developing and implementing policy and regulatory

approaches to reducing climate pollution….” Va. Code

§ 10.1-1183(B)(2). It is impossible to forecast which of

these state climate policies would pass must under

Petitioners’ muddled preemption test.

The Memorandum of Understanding establishing RGGI was

signed in 2005; RGGI’s first auction of carbon dioxide emissions

allowances occurred in 2008. RGGI, Elements of RGGI, https:/

/www.rggi.org/program-overview-and-design/elements (last visited July 29, 2026).

Even more, Virginia laws on mundane matters

could also come within the crosshairs of Petitioners’

rambling, “causal chain” theory of preemption. Like

the overwhelming majority of states, Virginia maintains a Commercial Property Assessed Clean Energy

(C-PACE) loan program to assist building owners with

energy-efficient upgrades to their properties. 4 The list

of eligible projects includes a host of measures that are

well-within a state’s traditional authority to manage:

“Energy efficiency improvements;” “Renewable energy

improvements;” and “Electric vehicle infrastructure

improvements,” to name a few. Va. Code § 15.2-958.3.

Even state regulations for the licensure of liquefied

petroleum gas fitters might be preempted if Petitioners have their way. These regulations call for the

revocation of a license if an operator performs their

work “incompetently as demonstrated by an egregious

or repeated violation of the standards,” Va. Code

§ 54.1-1134. When enforced, these provisions reduce

leaks from fossil fuels.

Virginia, like every state in the union, 5 also imposes

a motor vehicle fuel tax (i.e., gas tax), Va. Code § 58.12217, and maintains speed limits, Va. Code § 46.2-870.

Together, these policies have an unmistakable, upstream impact on reducing fossil-fuel emissions. See

e.g., Michael P. Vandenbergh, From Smokestack to

SUV: The Individual as Regulated Entity in the New

Era of Environmental Law, 57 Vand. L. Rev. 515, 556–

56 (2004) (discussing “state and local efforts to

Pace Equity Finance, States with Active C-PACE Financing,

https://www.pace-equity.com/c-pace-states/ (identifying 40 states

with C-PACE programs) (last visited July 23, 2026).

Tax Foundation, Gas Taxes by State, 2025, https://tax

foundation.org/data/all/state/gas-taxes-state/ (Sept. 2, 2025).

reduce emissions by reducing speed limits”). In the

Washington, D.C. region—where cars registered in

Maryland frequently travel into Virginia—traffic

congestion has long been a major source of air

pollution. Virginia addresses this problem with laws

designed to promote carpooling and establish highoccupancy vehicle lanes “to facilitate the rapid and

orderly movement of traffic to and from urban areas

during peak traffic periods.” Va. Code § 33.2-501.

All of these statutory initiatives have at least an

indirect effect on interstate greenhouse gas emissions;

none are preempted by the federal Clean Air Act, and

for good reason. Similar, state-regulated, renewable

energy programs have survived other constitutional

challenges.

Writing for the U.S. Court of Appeals for the Tenth

Circuit in Energy & Environment Legal Institute v.

Epel, 793 F.3d 1169 (10th Cir. 2015), then-Judge

Gorsuch authored the court’s opinion upholding

Colorado’s Renewable Portfolio Standard (RPS) in the

face of a dormant commerce clause challenge.

Colorado law required in-state electricity providers “to

ensure that 20% of the electricity they sell to Colorado

consumers comes from renewable sources.” Id. at

1170.

Coloradois part of an interconnected grid serving

eleven states and portions of Canada and Mexico.” Id.

at 1171. Challengers to the Colorado program claimed

that it would affect electricity prices out-of-state,

harming “out-of-state coal producers.” Id. The Tenth

Circuit acknowledged that the Colorado RPS program

would impact out-of-state energy prices, but found

those impacts did not cross any constitutional red

line: “we hardly mean to suggest non-price regulations don’t impact price in or out of state. In

today’s interconnected national marketplace such a

suggestion would be beyond naive.” Id. at 1173. The

Tenth Circuit nevertheless rejected a test that would

brand as unconstitutional “any state regulation that

‘control[s] ...conduct’” because such a test would “risk

serious problems of overinclusion.” Id. at 1175.

In sum, the “controls conduct” test evaluated in Epel

was rejected as woefully overbroad. It failed to account

for Colorado “standing upon her extreme rights,”

Georgia v. Tennessee Copper Co., 206 U.S. 230, 238-39

(1908), in implementing an RPS program. 6

Petitioners’ “causal chain” theory of preemption

suffers similar deficiencies, boldly overreaching into

areas of traditional state sovereignty. It fails to

provide any limiting principle for delineating the outer

bounds of implied preemption.

III. The cooperative federalism structure of

the Clean Air Act works to block

Petitioners’ broad overreach into areas of

traditional state control.

As stated above, Respondents’ state-law claims are

not in conflict with any federal regulation under the

Clean Air Act because the City and County of Boulder,

Colorado do not seek to regulate greenhouse gas

emissions. To the extent that Respondents’ state-law

case has an upstream impact on pollution, that

indirect impact (even if intentional) is outside of the

regulatory design of the CAA.

Decades before adoption of the modern Clean Air Act

Amendments of 1970, Justice Holmes famously heralded the role

of states in protecting their citizens, notwithstanding upstream

impacts on cross-border concerns, Georgia v. Tennessee Copper

Co., 206 U.S. 230, 237-39 (1908).

Impliedly extending the CAA to bar states from addressing these impacts would contradict the cooperative

federalism model that Congress established. The

Senate Report on the Clean Air Act’s citizen-suit

provision, 42 U.S.C. § 7604, CAA § 304, is crystal clear

on this point. The Report states:

“It should be noted, however, that the section

would specifically preserve any rights or

remedies under any other law. Thus, if damages could be shown, other remedies would

remain available. Compliance with standards

under this Act would not be a defense to a

common law action for pollution damages.”

S. Rep. 91-1196, at 38 (Sept. 17, 1970) (emphasis

added).

What the statutory background provides, the text

confirms. Congress recognizes that air pollution “is the

primary responsibility of States and local governments,” 42 U.S.C. § 7401(a)(3), and expressly allows

states and localities to “adopt or enforce ... any requirement respecting control or abatement of air

pollution” above the national standards through its

Savings Clause, 42 U.S.C. § 7416. Nothing in the CAA

expresses a congressional intent to broadly preclude

state tort regimes.

Indeed, preservation of the states’ role in combatting air pollution has been a feature of the CAA

from Congress’s earliest amendments. The first major,

federal law on air pollution, the Air Pollution Control

Act of 1955, confirmed a vibrant role for states in

remedying air-pollution harms: “it is hereby declared

to be the policy of Congress to preserve and protect the

primary responsibilities and rights of the States and

local governments in controlling air pollution.” Pub. L.

159, 69 Stat. 322 (July 14, 1955). See also Arnold W.

Reitze, Jr., A Century of Air Pollution Control Law:

What’s Worked; What’s Failed; What Might Work, 21

Envtl. L. 1549, 1585 (1991) (documenting the origins

of the Clean Air Act). A principal role for state and

local actors was reaffirmed by the Clean Air Act of

1963, which announced that “municipal, State, and

interstate action to abate air pollution shall be

encouraged and shall not be displaced by Federal

enforcement action.” Pub. L. 88-206, 77 Stat. 396 (Dec.

17, 1963).

It is therefore incongruous for Petitioners to argue

field preemption, Br. of Pet’rs at 38-39, given the

CAA’s long history of preserving an essential role for

states in remedying air-pollution injuries. See, e.g.,

Commonwealth of Virginia v. Browner, 80 F.3d 869,

877 (4th Cir. 1996), cert. denied 519 U.S. 1090 (1997)

(holding that language on Title V permits “creates a

floor of rights, rather than a ceiling, and ensures that

the CAA does not inadvertently diminish standing

rights previously granted under state laws.”).

Field preemption is especially inappropriate here

because the EPA has issued a final rule “repudiating

the EPA’s positions since 2009” and is now controversially asserting that the Clean Air Act “does not

authorize the EPA to prescribe GHG emission standards based on global climate change concerns….” See

91 Fed. Reg. at 7695. Even amicus curiae in support of

Petitioners, the American Petroleum Institute (API),

has raised concerns about EPA’s rationale. In

comments filed with the agency, API cautioned:

“[T]he U.S. Supreme Court already decided

the question of whether … EPA may regulate

GHGs under the CAA for their effect on global

climate. In its landmark Massachusetts v.

EPA decision, the Court squarely concluded

‘that it does.’ … Broader context also counsels

against an approach that could potentially

conflict with the Supreme Court’s decision in

Massachusetts v. EPA.”

See Comments of the American Petroleum Institute on

the Proposed Rule Entitled “Reconsideration of 2009

Endangerment Finding and Greenhouse Gas Vehicle

Standards,” Docket ID No. EPA-HQ-OAR-2025-0194

(submitted Sep 22, 2025), https://www.regulation

s.gov/comment/EPA-HQ-OAR-2025-0194-0869.

In International Paper Co. v. Ouellette, this Court

worried that some nuisance lawsuits might “circumvent the NPDES permit system” of the Clean

Water Act. 479 U.S. 481, 494 (1987). EPA is now

objecting to any federal permit system under the

Clean Air Act for climate-related harms. EPA is not

occupying the field; it is attempting to abandon it.

IV. The presumption against preemption is

necessary to protect states’ sovereignty.

At their core, Petitioners’ claims are premised on an

unusual presumption—that the Court should assume

the existence of a “uniform federal law … in the

context of global climate change.” Br. for Pet’rs, at 13.

This argument flouts this Court’s longstanding respect

for the role of states.

For decades, this Court’s precedents have confirmed

not just that a presumption against preemption exists,

but why it is necessary to preserve the integrity of

quasi-sovereign states. See, e.g., Rice v. Santa Fe

Elevator Corp., 331 U.S. 218, 230 (1947) (“we start

with the assumption that the historic police powers of

the States were not to be superseded by the Federal

Act unless that was the clear and manifest purpose of

Congress.”); Gregory v. Ashcroft, 501 U.S. 452, 461

(1991) (“Congress should make its intention ‘clear and

manifest’ if it intends to pre-empt the historic powers

of the States…. This plain statement rule is nothing

more than an acknowledgment that the States retain

substantial sovereign powers under our constitutional

scheme, powers with which Congress does not readily

interfere.”).

As Justice Scalia confirmed, “There is no federal

pre-emption in vacuo, without a constitutional text or

a federal statute to assert it…. [P]re-emption, if it is

intended, must be explicitly stated.” Puerto Rico Dep’t

of Consumer Affairs. v. Isla Petroleum Corp., 485 U.S.

495, 503-04 (1988). With this framework intact, state

tort regimes that have an upstream impact on areas of

federal regulation have withstood preemption challenges across a wide array of tort-law contexts.

These include cases implicating:

(1) pharmaceuticals, Wyeth v. Levine, 555 U.S. 555,

573 (2009) (“Impossibility pre-emption is a demanding

defense. On the record before us, Wyeth has failed to

demonstrate that it was impossible for it to comply

with both federal and state requirements.”);

(2) nuclear safety, Silkwood v. Kerr-McGee Corp.,

464 U.S. 238, 256 (1984) (“No doubt there is tension

between the conclusion that safety regulation is the

exclusive concern of the federal law and the conclusion

that a state may nevertheless award damages based

on its own law of liability. But… Congress intended to

stand by both concepts and to tolerate whatever

tension there was between them.”);

(3) pesticides, Bates v. Dow Agrosciences LLC, 544

U.S. 431, 449 (2005) (“Even if Dow had offered us a

plausible alternative reading of [a statutory preemption clause]—indeed, even if its alternative were

just as plausible as our reading of that text—we would

nevertheless have a duty to accept the reading that

disfavors pre-emption…. The long history of tort

litigation against manufacturers of poisonous substances adds force to the basic presumption against preemption.”); and

(4) tobacco, Cipollone v. Liggett Group, Inc., 505 U.S.

504, 528–29 (1992) (opinion of Stevens, J.) (a plaintiff’s

“fraudulent-misrepresentation claims… with respect

to advertising and promotions… are not pre-empted by

[express preemption clause in the Federal Cigarette

Labeling and Advertising Act]. Such claims are

predicated not on a duty ‘based on smoking and health’

but rather on a more general obligation—the duty not

to deceive.”).

Cipollone is an especially apt analog, as the

plaintiffs there sought recovery for smoking-related

injuries, but were not attempting to regulate on the

public-health impacts of tobacco use. By the same

token, the City and County of Boulder are seeking

recovery for climate-related injuries already incurred

and are not attempting to regulate greenhouse gas

pollution. In Cipollone, this Court upheld a plaintiff’s

right to seek state-law damages based on Failure to

Warn, Fraudulent Misrepresentation, Conspiracy to

Misrepresent or Conceal Material Facts. 505 U.S. at

524-30. These are exactly the kind of traditional

common-law claims that Respondents have raised

here. 7

An analogous distinction was noted by the Supreme Court of

Montana in Held v. Montana, 580 P.3d 1235 (Mont. 2024). There,

The Court’s most recent case on preemption,

Monsanto v. Durnell, 609 U.S. ___, ___, No. 24-1068,

slip op. at 9 (June 25, 2026) (Opinion of the Court),

reaffirms this approach as it relies on a clear and

explicitly worded preemption clause in the Federal

Insecticide, Fungicide, and Rodenticide Act, 7 U.S.C.

§ 136v(b) (States “shall not impose or continue in effect

any requirements for labeling or packaging in addition

to or different from those required under this

subchapter.”). See also Hencely v. Fluor Corp., 608

U.S. ___, ___, 146 S. Ct. 1086, 1096 (2026) (“Congress

knows full well how to make its intention to preclude

private liability known.”) (internal citation omitted).

Moreover, scholarship on preemption has understood these cases and the Court’s presumption against

preemption as necessary to create a structure that

preserves state sovereignty. See Jonathan Adler,

Displacement and Preemption of Climate Nuisance

Claims, 17 J. L. Econ. & Pol’y 217, 220 (2022) (“Under

longstanding precedent, it is more difficult to preempt

state common law than it is to displace federal

common law.”); Caleb E. Nelson, Preemption, 86 Va. L.

Rev. 225–305, 231–32 (2000) (“Under the Supremacy

Clause, preemption occurs if and only if state law

contradicts a valid rule established by federal law, and

the mere fact that federal law serves certain purposes

does not automatically mean that it contradicts everything that might get in the way of those purposes”).

the court sided with plaintiffs, who articulated climate-related

harms (wildfires, extreme heat, drought, “disappearing glaciers

in Montana”), id. at 1256, and claimed relief via the Montana

Constitution’s guarantee to “a clean and healthful environment.”

id. at 1248-49. The Montana high court explained, “[O]ur focus

here … is not on redressing climate change, but on redressing

[plaintiffs’ state-law] constitutional injuries ….” Id. at 1254.

Even if there were “sound policy reasons to treat

greenhouse gases differently,” that would be a determination “made by legislators, not judges.” Adler, 17

J.L. Econ. & Pol’y at 246 (2022); see also Tennessee

Copper Co., 206 U.S. at 239 (“Whether Georgia, by

insisting upon this claim, is doing more harm than

good to her own citizens, is for her to determine. The

possible disaster to those outside the state must be

accepted as a consequence of her standing upon her

extreme rights.”).

This Court’s “precedents require Congress to enact

exceedingly clear language if it wishes to significantly

alter the balance between federal and state power.”

United States Forest Service v. Cowpasture River

Preservation Association, 590 U.S. 604, 621–22 (2020).

See e.g., Hencely, 608 U.S. ___, ___, 146 S. Ct. 1086,

1098 (2026) (“[T]he mere fact that the conduct here

occurred overseas in a warzone perhaps makes this a

good case for Congress to intervene, but it does not

give courts a license to bar all such suits on their own

authority.”).

In short, preempting state-law claims on climate

change-related injuries risks the very same “costs to

cooperative federalism and individual liberty” that the

Court rightly identified in Virginia Uranium, 587 U.S.

at 775.

CONCLUSION

For the reasons stated above, members of the

Virginia General Assembly as amici curiae ask this

Court to affirm the decision of the Colorado Supreme

Court and reject Petitioners’ attempt to federalize

state tort law claims seeking damages for climate

change-related injuries.

Respectfully submitted,

CALE JAFFE

Counsel of Record

DIRECTOR, ENVIRONMENTAL LAW AND

COMMUNITY ENGAGEMENT CLINIC

UNIVERSITY OF VIRGINIA SCHOOL OF LAW

580 Massie Road

Charlottesville, VA 22903

(434) 924-4776

cjaffe@law.virginia.edu

Counsel to the Hon. Scott A. Surovell,

Virginia Senate Majority Leader, and

Sen. R. Creigh Deeds, Del. Katrina E.

Callsen, and Del. Amy J. Laufer,

Members of the Virginia General

Assembly, as Amici Curiae in Support

of Respondents

August 3, 2026

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.