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

NO. 25-170

In the

Supreme Court of the United States

_______________________

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

Petitioners,

v.

COUNTY COMMISSIONERS OF BOULDER COUNTY, ET AL.,

Respondents.

________________

On Writ of Certiorari to the

Supreme Court of Colorado

________________

BRIEF OF COLORADO, CALIFORNIA, AND 17

OTHER STATES AS AMICI CURIAE IN

SUPPORT OF RESPONDENTS

________________

ROB BONTA

CARRIE E. NOTEBOOM

Attorney General of California Assistant Deputy Attorney

General

SAMUEL T. HARBOURT

ROBYN WILLE

Solicitor General

First Assistant Attorney

PHILIP J. WEISER

General

Attorney General of Colorado

CORY HALLER

RUSSELL D. JOHNSON

Senior Assistant Attorney

Deputy Solicitor General

General

Counsel of Record

GABBY FALCON

Assistant Attorney General

Office of the Colorado

Attorney General

CAMERON BONNELL

1300 Broadway, 10th Floor

Assistant Attorney General

Denver, Colorado 80203

Fellow

Russell.Johnson@coag.gov

(720) 508-6000

Counsel Continues on Signature Page

TABLE OF CONTENTS

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

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

INTERESTS OF AMICI ............................................. 1

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

ARGUMENT ............................................................... 4

I.

The Court’s analysis of its jurisdiction under

28 U.S.C. § 1257 should continue to focus on

the specific state proceedings at issue, not

generalizations and high-level comparisons. ..... 4

II. The States have developed both common law

claims and defenses, and state courts should

be trusted to correctly apply the numerous

doctrines and rules that protect defendants

from meritless claims. ......................................... 7

A. State common law tort claims have long

allowed plaintiffs to seek relief for their

harms, evolving over time to reflect the

complexity of modern life. ............................ 8

B. State common law tort claims are subject

to multiple safeguards that protect

against meritless claims............................. 13

III. The Constitution’s structure is not a valid

basis on which to preempt state common law

claims. ................................................................ 15

ii

A. The Court has repeatedly denied theories

of preemption that are untethered to

constitutional text. ..................................... 16

B. A vaguely described federal interest over

interstate pollution and climate change

cannot preempt Boulder’s state common

law claims. .................................................. 20

C. Petitioners’ theory would usurp the role

of state legislatures and state courts in

policing the bounds of common law

claims to protect both businesses and

state residents. ........................................... 25

CONCLUSION ......................................................... 29

iii

TABLE OF AUTHORITIES

Cases

Altria Grp., Inc. v. Good,

555 U.S. 70 (2008) .............................................. 7, 20

Am. Elec. Power Co. v. Connecticut,

564 U.S. 410 (2011) .................................... 18, 22, 23

Am. Fire & Cas. Co. v. Finn,

341 U.S. 6 (1951) ...................................................... 4

Bender v. Williamsport Area Sch. Dist.,

475 U.S. 534 (1986) .................................................. 4

Beraglia v. Owens-Corning Fiberglass Corp.,

606 So. 2d 1213 (Fla. Ct. App. 1992) ..................... 28

Bonito Boats Inc. v. Thunder Craft Boats

Inc.,

489 U.S. 141 (1989) ................................................ 22

Borel v. Fibreboard Paper Prods. Corp.,

493 F.2d 1076 (5th Cir. 1973)................................ 28

Boyle v. United Techs. Corp.,

487 U.S. 500 (1988) .......................................... 22, 24

Buckman Co. v. Plantiffs’ Legal Comm.,

531 U.S. 341 (2001) ................................................ 22

Chamber of Com. v. Whiting,

563 U.S. 582 (2011) ................................................ 16

Cipollone v. Liggett Group, Inc.,

644 F. Supp. 283 (D.N.J. 1986) ............................. 28

Ciraolo v. City of New York,

216 F.3d 236 (2d Cir. 2000) ................................... 11

iv

City of Burbank v. Lockheed Air Terminal

Inc.,

411 U.S. 624 (1973) ................................................ 20

Costarelli v. Massachusetts, 421 U.S. 193

(1975) .................................................................... 4, 5

Fisher v. District Court,

424 U.S. 382 (1976) .................................................. 6

Ford Motor Co. v. Mont. Eighth Judicial

Dist. Ct.,

592 U.S. 351 (2021) ................................................ 19

Franchise Tax Bd. v. Hyatt,

538 U.S. 488 (2003) ................................................ 19

Franchise Tax Bd. v. Hyatt,

587 U.S. 230 (2019) ................................................ 16

Freightliner Corp. v. Myrick,

514 U.S. 280 (1995) ................................................ 24

Funk v. U.S.,

290 U.S. 371 (1933) .......................................... 12, 13

Gade v. Nat’l Solid Wastes Mgmt. Ass’n,

505 U.S. 88 (1992) .................................................. 16

Gen. Motors Corp. v. United States,

496 U.S. 530 (1990) ................................................ 23

Georgia v. Tennessee Copper Co.,

206 U.S. 230 (1907) ................................................ 18

Gospel Army v. City of Los Angeles,

331 U.S. 543 (1947) .................................................. 6

Hencely v. Fluor Corp.,

146 S. Ct. 1086 (2026)................................ 18, 22, 24

v

Hillsborough County v. Automated Med.

Labs., Inc.,

471 U.S. 707 (1985) ................................................ 21

Hurtado v. California,

110 U.S. 516 (1884) ................................................ 13

Illinois v. City of Milwaukee,

406 U.S. 91 (1972) .................................................. 18

In re Nat’l Prescription Opiate Litigation,

477 F. Supp. 3d 613 (N.D. Ohio 2020) .................. 27

In re Tobacco II Cases,

207 P.3d 20 (Cal. 2009) .......................................... 28

Int’l Paper Co. v. Ouellette,

479 U.S. 481 (1987) ................................................ 23

Jefferson v. City of Tarrant,

522 U.S. 75 (1997) ................................................ 5, 7

Kansas v. Garcia,

589 U.S. 191 (2020) .......................................... 16, 17

Keeton v. Hustler Magazine, Inc.,

465 U.S. 770 (1983) ................................................ 19

Kokkonen v. Guardian Life Ins. Co.,

511 U.S. 375 (1994) .................................................. 4

Lockwood v. AC & S, Inc.,

744 P.2d 605 (Wash. 1987) .................................... 28

M. L. Stewart & Co. v. Marcus,

207 N.Y.S. 685 (Sup. Ct. 1924) ................................ 9

MacPherson v. Buick Motor Co.,

111 N.E. 1050 (1916) ............................................. 10

Marbury v. Madison, 1 Cranch (5 U.S.)

137 (1803) ................................................................. 4

vi

Maryland v. Louisiana,

451 U.S. 725 (1981) .................................................. 8

Medtronic, Inc. v. Lohr,

518 U.S. 470 (1996) ................................................ 21

Missouri v. Illinois,

180 U.S. 208 (1901) ................................................ 18

Mitchell v. Maurer,

293 U.S. 237 (1934) .................................................. 4

Monsanto Company v. Durnell,

146 S. Ct. 2001 (2026)............................................ 24

Nat’l Pork Producers Council v. Ross,

598 U.S. 356 (2023) ................................................ 19

New York v. New Jersey,

256 U.S. 296 (1921) ................................................ 18

North Carolina, ex rel. Cooper v. Tenn. Valley

Auth.,

615 F.3d 291 (4th Cir. 2010).................................. 22

Nw. Austin Mun. Utility Dist. No. One v.

Holder,

557 U.S. 193 (2009) ................................................ 17

O’Dell v. Espinoza,

456 U.S. 430 (1982) .................................................. 5

P.R. Dep’t of Consumer Affairs v. Isla

Petroleum Corp.,

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

Palsgraf v. Long Island R.R. Co.,

162 N.E. 99 (1928) ............................................. 8, 11

People v. ConAgra Grocery Prods. Co.,

17 Cal. App. 5th 51 (Ct. App. 2017) ...................... 28

vii

PruneYard Shopping Centers v. Robbins,

447 U.S. 74 (1980) .................................................. 21

Republic Natural Gas Co. v. Oklahoma,

334 U.S. 62 (1948) .................................................... 5

Rescue Army v. Mun. Ct. of City of Los

Angeles,

331 U.S. 549 (1947) .................................................. 6

Ruhrgas AG v. Marathon Oil Co.,

526 U.S. 574 (1999) .................................................. 5

Smith v. Turner,

48 U.S. 283 (1849) .................................................. 21

South Carolina v. Katzenbach,

282 U.S. 301 (1966) ................................................ 17

Texas Indus., Inc. v. Radcliff Materials, Inc.,

451 U.S. 630 (1981) ................................................ 22

United States v. Carroll Towing Co.,

159 F.2d 169 (2d Cir. 1947) ................................... 10

United States v. Locke,

529 U.S. 89 (2000) .................................................. 22

Virginia Uranium, Inc. v. Warren,

587 U.S. 761 (2019) .......................................... 20, 21

Whitmarsh v. Comm.,

316 N.E. 610 (1974) ................................................. 5

Wos v. E.M.A. ex rel. Johnson,

568 U.S. 627 (2013) ................................................ 25

Wyeth v. Levine,

555 U.S. 555 (2009) .................................... 17, 20, 24

Young v. Masci,

289 U.S. 253 (1933) ................................................ 19

viii

Statutes

28 U.S.C. § 1257 ................................................. 1, 2, 4

Ala. Code § 6-5-792 (2021)........................................ 26

Fla. Stat. Ann. § 768.38 (2021) ................................ 26

Iowa Code Ann. § 686D.5 (2020) .............................. 26

Kan. Stat. Ann. § 60-5504 (2020) ............................. 26

La. Stat. Ann. § 9:2800.25 (2020)............................. 26

Mich. Comp. Laws § 691.1455 (2020) ...................... 26

Miss. Code Ann. § 11-71-5 (2020) ............................ 26

Nev. Rev. Stat. § 41.835 (2020) ................................ 26

Okla. Stat. tit. 76, § 111 (2021) ................................ 26

Other Authorities

Dan B. Dobbs, Paul T. Hayden & Ellen M.

Bublick, The Law of Torts (2d ed. 2016) ........... 8, 25

Donald G. Gifford, Technological Triggers to

Tort Revolutions: Steam Locomotives,

Autonomous

Vehicles,

and

Accident

Compensation, 11 J. Tort L. 71 (2018) .............. 9, 10

G. Edward White, The Emergence and

Doctrinal Development of Tort Law, 18701930, 11 U. St. Thomas L.J. 463 (2014) ................ 11

Geoff Mulvihill & John Seewer, Purdue

Pharma, US States Agree to New Opioid

Settlement, Assoc. Press (Mar. 3, 2022), ............... 27

H.B. 76, 32d Leg. (Alaska 2021) .............................. 26

ix

Heidi L. Feldman, From Liability Shields to

Democratic Theory: What We Need from Tort

Theory Now, 14 J. Tort L. 373 (2021) ................... 26

Jan Hoffman, Drug Distributors and J.&J.

Reach $26 Billion Deal to End Opioid

Lawsuits, N.Y. Times (Nov. 11, 2021) ................... 27

Kate Markey, Air Pollution as Public

Nuisance:

Comparing

Modern-Day

Greenhouse

Gas

Abatement

with

Nineteenth-Century Smoke Abatement, 120

Mich. L. Rev. 1535 (2022) ...................................... 11

Lawrence Friedman, A History of American

Law (4th ed. 2019) ............................................. 9, 10

Legis. B. 39(3), 107th Leg., 1st Sess. (Neb.

2021) ....................................................................... 26

Michael J. Purcell, Settling High: A Common

Law Public Nuisance Response to the Opioid

Epidemic, 52 Colum. J.L. & Soc. Probs. 135

(2018) ...................................................................... 27

Patrick J. Kelley, The Carrol Towing

Company Case and the Teaching of Tort

Law, 45 St. Louis U. L.J. 731 (2001)..................... 10

Restatement (Third) of Torts: Apportionment

Liab. (2000) ...................................................... 13, 14

Restatement (Third) of Torts: Phys. & Emot.

Harm (2010) ..................................................... 13, 14

Robert M. Ackerman, Tort Law and

Federalism:

Whatever

Happened

to

Devolution?, 14 Yale L. & Pol’y Rev. 429

(1996) ........................................................................ 9

x

Valerie Bauman, States, Cities Eye $26

Billion Deal: Opioid Litigation Explained,

Bloomberg L. (July 26, 2021) ................................ 27

Rules

90 Fed. Reg. 25784 (June 17, 2025) ......................... 23

91 Fed. Reg. 7686 (Feb. 18, 2026) ............................ 23

Mont. R. App. Civ. P. 17 ............................................. 6

INTERESTS OF AMICI

State courts and state common law claims play an

important role in the resolution of disputes great and

small. Anyone who has been harmed—whether a large

corporation, a State or local government, or a private

citizen—can bring state common law claims in state

courts seeking redress. And defendants can rely on

state courts to resolve claims fairly, consistent with

the protections state law provides. Attempts to short

circuit state court processes or preempt state law

should be met with a healthy skepticism that respects

our federal system.

Amici here, the States of Colorado, California, Arizona, Connecticut, Delaware, Hawai’i, Illinois,

Maine, Maryland, Massachusetts, Michigan, Nevada,

New Jersey, New York, Oregon, Rhode Island, Vermont, and Washington, and the District of Columbia

(collectively, “Amici States”), including some that have

brought their own actions against fossil fuel companies, have a strong interest in preserving the careful

balance the Constitution struck between the States

and the federal government. That interest is implicated here in two important ways.

First, consistent with the Constitution, Congress

gave this Court limited jurisdiction to review final

judgments rendered by state courts. See 28 U.S.C.

§ 1257. To avoid prematurely intervening in state

court litigation, the Court should continue its long history of thoughtfully examining state court proceedings

to determine whether it has statutory jurisdiction instead of relying on high-level comparisons and generalizations.

2

Second, Amici States also have an interest in the

continuing availability of state common law claims absent a clear and textually grounded conflict with federal law. To hold otherwise could usher in a new and

unjustified preemption regime that fundamentally undermines the viability of state common law remedies,

leaving those who have been harmed without a path

to being made whole.

SUMMARY OF THE ARGUMENT

I. As courts of limited jurisdiction, federal courts

must closely scrutinize the basis for exercising their

jurisdiction. This Court has a long history of carefully

reviewing state court proceedings to ensure that it has

jurisdiction under 28 U.S.C. § 1257, which both conserves the Court’s resources and contributes to productive relationships between state and federal

courts. Because state courts each have their own rules

and processes, the Court must interrogate the specific

state proceeding at issue to determine whether it has

jurisdiction, as opposed to relying on broad generalizations based on other States’ laws and processes, as

Petitioners and certain amici argue is appropriate

here. Performing that detailed review here, demonstrates the Court lacks jurisdiction.

II. Concerns regarding the merits of Boulder’s suit

are not a valid basis for preempting state common law

tort claims. State common law provides not only remedies for injured parties, but also protections for alleged tortfeasors, such as proximate cause, allocation

of fault, foreseeability, and others. State courts should

be trusted to faithfully apply the law, and any suggestion that merits concerns justify preempting state

common law claims should be rejected. If Boulder’s

3

claims are meritless, state courts can dismiss them on

that basis. Preemption is not the answer.

III. There is nothing in this Court’s preemption

jurisprudence that would justify preempting state

common law claims 1 based on little more than a brooding interest ambiguously arising out of the structure

of the Constitution. Rather, a specific conflict between

the Constitution and state common law claims must

exist before injured parties are deprived of their day

in court. Any other approach could create a significant

imbalance between the States and the federal government inconsistent with the Constitution and allow

courts to make policy judgments best left to the legislative branch.

1 All that remains at issue in this case are state common law

claims; Boulder’s statutory claim under the Colorado Consumer

Protection Act was dismissed by the state trial court on purely

state law grounds. Pet. App. 138a. Accordingly, whether that

statutory claim could be preempted by federal law under Petitioners’ theory is a separate and distinct issue that was not considered by the Colorado Supreme Court and is thus not an issue

before this Court. Pet. Br. at 9; U.S. Br. at 6 n.2. Further, state

statutory claims form an important aspect of each State’s exercise of its retained authority under the Tenth Amendment. It

would be a significant invasion of state sovereignty to weigh in

on such claims without the benefit of the full context in which

those claims arise. Thus, despite discussions regarding state statutory regimes, see Br. of Am. Petroleum Inst. as Amici Curiae in

Support of Petitioners at 12–15, this Court should focus only on

the specific claims presently before it.

4

ARGUMENT

I.

The Court’s analysis of its jurisdiction under

28 U.S.C. § 1257 should continue to focus on

the specific state proceedings at issue, not

generalizations and high-level comparisons.

“Federal courts are courts of limited jurisdiction,”

see, e.g., Kokkonen v. Guardian Life Ins. Co., 511 U.S.

375, 377 (1994), and they may exercise jurisdiction

only when so “authorized by Article III of the Constitution and the statutes enacted by Congress pursuant

thereto.” Bender v. Williamsport Area Sch. Dist., 475

U.S. 534, 541 (1986) (citing Marbury v. Madison, 1

Cranch (5 U.S.) 137, 173–80 (1803)). As such, federal

appellate courts have “a special obligation” to ensure

that they have jurisdiction to hear the merits of a dispute. Id. (citing Mitchell v. Maurer, 293 U.S. 237, 244

(1934). Their jurisdiction must be “carefully guarded

against expansion by judicial interpretation.” Am. Fire

& Cas. Co. v. Finn, 341 U.S. 6, 17 (1951).

In line with those principles, Congress granted

this Court limited jurisdiction over state court proceedings, allowing review only of “[f]inal judgments or

decrees rendered by the highest court of a State” under specific circumstances. 28 U.S.C. § 1257(a)

(“Section 1257”). Section 1257’s final judgment requirement preserves this Court’s resources by ensuring the Court does not intervene in “state proceedings

when the underlying dispute may be otherwise resolved.” See Costarelli v. Massachusetts, 421 U.S. 193,

196 (1975) (per curiam). And “close observance of [the

final judgment] limitation . . . is an important factor

in securing harmonious State-federal relations.” Republic Natural Gas Co. v. Oklahoma, 334 U.S. 62, 67

5

(1948) (citation modified). Indeed, “federal and state

courts are complementary systems for administering

justice in our Nation. Cooperation and comity, not

competition and conflict, are essential to the federal

design.” Ruhrgas AG v. Marathon Oil Co., 526 U.S.

574, 586 (1999).

The Court has recognized the importance of following Section 1257’s requirements, analyzing state

court processes in detail to ensure that it has jurisdiction when the issue arises. For example, in Costarelli,

the Court examined the proceedings in Massachusetts

state court and recent case law from the Supreme Judicial Court of Massachusetts to determine that the

process involved had not resulted in the issuance of a

final judgment sufficient to give this Court jurisdiction

under Section 1257. Costarelli, 421 U.S. at 195 (citing

Whitmarsh v. Comm., 316 N.E. 610 (1974)).

Similarly, in Jefferson v. City of Tarrant, 522 U.S.

75 (1997), the Court considered proceedings before the

Alabama Supreme Court. Even though the appeal to

the Alabama Supreme Court was “avowedly interlocutory,” the Court still analyzed the proceedings in Alabama state court—both those that had occurred and

those that would follow the Alabama court’s decision—

and determined it lacked jurisdiction. 522 U.S. at

81–84. See also O’Dell v. Espinoza, 456 U.S. 430 (1982)

(per curiam) (dismissing a petition for certiorari from

a decision of the Colorado Supreme Court remanding

the case to the trial court for lack of jurisdiction because the decision was not final).

Other state processes have resulted in the Court

finding it has jurisdiction. In fact, the Court has even

split apart companion cases where its analysis of the

6

specific state proceedings in each case resulted in one

satisfying the final-judgment requirement but not the

other. Compare Gospel Army v. City of Los Angeles,

331 U.S. 543, 546–48 (1947) (holding the final-judgment rule was not satisfied based on the processes and

specific orders involved), with Rescue Army v. Mun. Ct.

of City of Los Angeles, 331 U.S. 549, 565 (1947) (holding the Court had jurisdiction because the judgment

was final).

The approach in Fisher v. District Court, 424 U.S.

382 (1976), is of a piece with these other cases. There,

the Court looked to the Montana Constitution, Montana’s appellate rules, and Montana case law to determine that the Montana Supreme Court’s writ of

supervisory control was a final judgment sufficient to

confer jurisdiction. Id. at 384 n.7 (citing, inter alia,

Mont. Const. art. VII, § 2(1) & (2); Mont. R. App. Civ.

P. 17(a), and State ex rel. Amsterdam Lumber, Inc. v.

Dist. Ct., 516 P.2d 378, 380–81 (Mont. 1973)). The

Court then relied on that analysis for a similar matter

also arising in Montana. Atlantic Richfield Co. v.

Christian, 590 U.S. 1, 12 (2020).

But as Boulder notes, Colorado’s Constitution, appellate rules, and case law—which are all that are at

issue here—are not the same as Montana’s. Resp. Br.

18–22. And consistent with how this Court has examined jurisdiction in other circumstances, it must engage in a rigorous analysis here. It should not base its

jurisdictional determination in this case on generalizations or surface-level comparisons to cases examining how another State’s highest court exercises its

authority, as Petitioners and certain amici advocate.

Pet. Br. 18; see generally Br. of Frmr. State Supreme

7

Court Justices in Support of Pet’rs. Indeed, as City of

Tarrant shows, even the labels state courts apply do

not obviate the need to scrutinize the state proceedings to assess jurisdiction. City of Tarrant, 522 U.S. at

81.

Individualized analysis is necessary because state

courts are under no obligation to exercise their authority in the same way or to ensure that their procedures

fit cleanly within Section 1257. Instead, each State

creates its own rules and procedures based on its constitution and laws and taking into account the needs

and desires of its institutions and their constituents.

It is then incumbent on this Court to determine

whether the process used resulted in a final judgment

or decree that can support jurisdiction under the

terms specified by Congress in Section 1257.

As with the cases discussed above, that analysis

should not be cut short through broad generalizations

about how state courts operate. Rather, this Court

should focus on the specific procedure used to determine whether it has jurisdiction. As Boulder makes

clear, doing so here demonstrates that the Court lacks

jurisdiction under Section 1257. Resp. Br. 18–23.

II. The States have developed both common

law claims and defenses, and state courts

should be trusted to correctly apply the numerous doctrines and rules that protect defendants from meritless claims.

The essential element of a preemption claim is a

conflict between federal and state law. See Altria Grp.,

Inc. v. Good, 555 U.S. 70, 76 (2008) (citing Maryland

v. Louisiana, 451 U.S. 725, 746 (1981)). Yet, Petitioners and some amici suggest preemption is appropriate

8

here because Boulder’s claims lack merit. See, e.g.,

Pet. Br. at 36−37; Br. of the United States at 16–17

(“U.S. Br.”). These concerns ignore the basic principles

of this Court’s preemption jurisprudence. And they

give short shrift to the very nature of tort law, which

has evolved—and continues to evolve—to reflect and

balance States’ sovereign interests in protecting people who are harmed and in shielding defendants from

meritless claims. The preemption analysis Petitioners

propose does not justify usurping the States’ role in

resolving claims like those Boulder asserts here. State

courts can and should be trusted to properly apply tort

law to weed out meritless claims. Federal preemption

is not the answer to merits concerns.

A. State common law tort claims have long

allowed plaintiffs to seek relief for their

harms, evolving over time to reflect the

complexity of modern life.

By compensating victims and vindicating public

and private rights, tort law provides an important

mechanism that empowers litigants to seek relief for

their injuries. Tort law is rooted in the medieval English writ of trespass on the case, which recognized a

societal interest in providing remedies for indirect or

consequential harm. Dan B. Dobbs, Paul T. Hayden &

Ellen M. Bublick, The Law of Torts § 17 (2d ed. 2016);

cf. Palsgraf v. Long Island R.R. Co., 162 N.E. 99, 101

(1928) (describing the origins of the law of negligence).

“[S]ince the founding of the Republic, [tort law] has

been an area almost exclusively reserved to the

states.” Robert M. Ackerman, Tort Law and Federalism: Whatever Happened to Devolution?, 14 Yale L. &

Pol’y Rev. 429, 430 (1996)).

9

Petitioners and their amici suggest that the supposed novelty of Boulder’s claims supports preemption. See, e.g., Pet. Br. at 34–35 (describing the breadth

of Boulder’s claims). But what Petitioners and their

amici see as a reason for preemption ignores one of tort

law’s defining characteristics. Building from its venerable origins, renewal and evolution are central aspects

of tort law, which has repeatedly evolved to reflect

changing societal interests and emerging technological developments while continuing to serve its compensatory purpose. See Donald G. Gifford,

Technological Triggers to Tort Revolutions: Steam Locomotives, Autonomous Vehicles, and Accident Compensation, 11 J. Tort L. 71, 142 (2018) (noting that

“waves of technological change account for the most

significant changes in American tort law”).

Many scholars attribute the evolution of tort law

to a desire to balance the need to provide compensation to injured parties with a desire to facilitate continued economic development. See, e.g., Lawrence

Friedman, A History of American Law, 444 (4th ed.

2019) (positing that judges reduced tort liability to a

standard of ordinary care “to limit damages to some

moderate measure” so that capital could “be spared for

its necessary work”); see also M. L. Stewart & Co. v.

Marcus, 207 N.Y.S. 685, 691 (Sup. Ct. 1924) (“the

courts endeavor, wherever it can be done without too

radical a departure from recognized legal rules, to harmonize the necessities of a competitive industrial system of business with the teachings of morality”). In

accommodating these competing interests, tort law

evolved to require injured parties to show that their

injury was caused by a breach of a standard of care,

and to incorporate a number of affirmative defenses to

10

otherwise actionable conduct. Gifford, 11 J. Tort L. at

95.

Thus, the Industrial Revolution and the resultant

development of increasingly complex technologies—

along with the immense economic impacts and heightened risk of harm they created—presaged the development of modern tort law and its attendant

guardrails that prevent abuse of tort claims. Friedman, A History of American Law, 283–84 (attributing

the development of tort law and the doctrine of negligence to “the industrial revolution—the age of engines

and machines [which] . . . have a marvelous capacity

to cripple and maim.”).

For example, the advent of the automobile led to

the adoption of foreseeability in lieu of privity as a basis for product liability. See MacPherson v. Buick Motor Co., 111 N.E. 1050 (1916). And recognizing the

changes to the concept of “duty” wrought by a rapidly

industrializing society, Judge Learned Hand developed his foundational test for claims involving the reasonableness of a defendant’s conduct, which defined

the nature and extent of a defendant’s duty by comparing the burden of taking precautions to avoid harm

to the probability of the harm and the magnitude or

severity of the potential loss that would result. United

States v. Carroll Towing Co., 159 F.2d 169 (2d Cir.

1947); Patrick J. Kelley, The Carrol Towing Company

Case and the Teaching of Tort Law, 45 St. Louis U.

L.J. 731, 733 (2001). And, as the Industrial Revolution

shifted society from direct, face-to-face interactions to

complex, mechanized sequences of events, Justice

Cardozo entrenched the concept of proximate cause,

which limits a defendant’s liability to harm that is a

11

reasonably foreseeable consequence of their actions.

Palsgraf, 162 N.E. at 103; G. Edward White, The

Emergence and Doctrinal Development of Tort Law,

1870-1930, 11 U. St. Thomas L.J. 463, 513 (2014).

The law of nuisance followed a similar arc. As the

pollution caused by the rapid and unregulated growth

of the Industrial Revolution darkened skies, soiled

buildings, and caused significant personal harm,

courts struggled to formulate workable standards to

govern nuisance claims against existing and emerging

sources of pollution. Kate Markey, Air Pollution as

Public Nuisance: Comparing Modern-Day Greenhouse

Gas Abatement with Nineteenth-Century Smoke

Abatement, 120 Mich. L. Rev. 1535, 1552 (2022). Initially, courts largely rejected nuisance claims against

emerging industries. Id. at 1554. But as courts’ understanding of the risks of these new forms of pollution

grew and evolved, the law of nuisance evolved in parallel, first incorporating a balancing regime before

yielding to a prima facie nuisance for smoke pollution.

Id. at 1554–56. That evolution in tort law helped ensure that the cost of carelessly engaging in an activity

would be borne by the person who chooses to undertake it, as opposed to it being imposed on society at

large. Ciraolo v. City of New York, 216 F.3d 236, 243

(2d Cir. 2000) (Calabresi, J., concurring) (“One goal of

the tort system . . . is to ensure that actors bear the

costs of their activities.”).

Ignoring that history, Petitioners and their amici

suggest the supposed novelty of Boulder’s claims renders them unfit for adjudication under state tort law

and thus, somehow preempted. The United States

speculates, for example, that Boulder’s claims would

12

require Petitioners to pay all “costs of abating all

downstream effects in Boulder that Boulder attributes

to climate change.” U.S. Br. at 15. And it argues that

there are too “many indirect steps separat[ing] petitioners’ worldwide conduct from far-down-the-chain

effects in Boulder.” Id. at 24. Similarly, Alabama and

its amici States posit that Boulder’s claims are distinguishable from those in an “ordinary” suit, because

Boulder “does not allege that any particular defendant’s products caused any particular injury in Colorado.” Br. of Alabama, et al. in support of Pet’rs. at 26

(“Ala. Br.”). And Petitioners also contend that “the

chain of causation between [Petitioners’] conduct and

the asserted in-state injuries . . . is attenuated.” Pet.’

Br. at 36.

To the extent these concerns implicate novel issues, they fail to account for the “flexibility and capacity for growth” and “wise adaptation” at the heart of

the common law and reflected in tort law’s development. 2 Funk v. U.S., 290 U.S. 371, 382–83 (1933) (citation omitted). Assuming tort law is incapable of

addressing as-yet unlitigated injuries and causes of

action would be antithetical to our legal system. “[A]s

it was the characteristic principle of the common law

to draw its inspiration from every fountation [sic] of

justice, we are not to assume that the sources of its

supply have been exhausted. On the contrary, we

should expect that the new and various experiences of

our own situation and system will mould and shape it

into new and not less useful forms.” Id. (quoting Hurtado v. California, 110 U.S. 516, 530 (1884)). Indeed,

2 As noted infra at 13–15, these concerns do not implicate novel

issues; they are readily addressed by existing guardrails.

13

tort law has already developed tools that address the

concerns Petitioners and their amici raise.

B. State common law tort claims are subject to multiple safeguards that protect

against meritless claims.

State tort law does not operate in a vacuum. There

are recognized legal doctrines—including reasonableness, foreseeability, causation, comparative fault,

damages caps, and pro rata liability—that may ultimately limit Boulder’s entitlement to relief in this

case, if any. See generally Restatement (Third) of

Torts: Apportionment Liab. § 26 (2000); Restatement

(Third) of Torts: Phys. & Emot. Harm § 1 (2010). 3

These tools—more specifically, their application by

state courts to common law tort claims—undermine

arguments that the merits of Boulder’s claims justify

inventing new federal preemption principles to preclude them.

Petitioners and their Amici attempt to justify

preemption based on their concerns regarding the potential scope and breadth of Boulder’s claims. Pet. Br.

at 34–35 (describing the breadth of Boulder’s claims);

U.S. Br. at 25–26 (arguing that Boulder’s theory would

“invite suits targeting other nationwide or global phenomena with global (and thus local) effects”); Ala. Br.

at 26 (arguing that Boulder’s “case is more pernicious

than an ordinary tort” that could impose “a levy on the

3 Amici States cite to the Restatement (Third) of Torts when

discussing potential safeguards given Boulder’s statements that

choice of law remains unsettled with respect to its claims. See

Resp. Br. 30–31.

14

aggregate output of a global industry”). But those concerns about the breadth of liability animate the doctrine of proximate cause, which limits Boulder’s

recovery to those harms which it can prove are the reasonably foreseeable outcome of Petitioners’ actions,

unbroken by superseding causes. See generally Restatement (Third) of Torts: Phys. & Emot. Harm

§§ 29–36 (2010).

The United States also contends that Boulder’s

claims must be preempted because Petitioners’ actions

allegedly “played an infinitesimal role at most” in precipitating climate change, and Boulder’s claims fail to

“disambiguate which sources of emissions caused alleged harms in Boulder.” U.S. Br. at 23. Again, tort

law contemplates the apportionment of liability for

both divisible and indivisible damages. Restatement

(Third) of Torts: Apportionment Liab. § A18 (2000) (Liability of Multiple Tortfeasors for Indivisible Harm);

Restatement (Third) of Torts: Apportionment Liab.

§ 26 (2000) (Apportionment of Liability When Damages Can be Divided by Causation). The answer to the

United States’ concern is for Petitioners to advance arguments that take advantage of these doctrines. And

it will be up to the factfinder to determine whether Petitioners’ conduct is more than a “trivial contribution”

to Boulder’s harms. Restatement (Third) of Torts:

Phys. & Emot. Harm § 36 (2010).

Ultimately, if Boulder’s claims lack merit for

these reasons or others, Petitioners can raise those issues in Colorado state court to test and defend against

Boulder’s claims. Every day, state courts assess merit,

weigh evidence, and enforce limits even in the most

complex cases. State courts are capable of requiring a

15

plaintiff to prove harm, fault, causation, and the extent of any damages attributable to a defendant’s actions. And States are free to develop and modify these

doctrines to reflect their unique interests and concerns. This divergence does not implicate the Supremacy Clause or any constitutional infirmity; it is a

feature of our federal system. To suggest otherwise

would undermine state law and threaten the evolution

of a liability regime reflecting a collective effort to balance and accommodate the interest in ensuring compensation for foreseeable harms with the desire to

encourage and facilitate otherwise beneficial activities. In other words, preempting state law because of

concerns about a claim’s merits has no place in the

structure of our federal system.

III. The Constitution’s structure is not a valid

basis on which to preempt state common law

claims.

Petitioners urge this Court to conclude that Boulder’s claims must be preempted because they undermine our federal system. See Pet. Br. at 22, 26–27. But

what Petitioners advocate for is nothing less than a

judicially crafted liability shield for the fossil fuel industry based on arguments conjured from implications they would read into the Constitution, not its

text.

This Court has repeatedly denied theories of

preemption that rest on abstract references to the

Constitution’s structure or brooding federal interests

untethered to constitutional text. There is no reason

for the Court to abandon that approach here.

16

A. The Court has repeatedly denied theories of preemption that are untethered

to constitutional text.

Neither Petitioners nor their amici cite any constitutional text supporting their preemption theory.

Instead, they rely on purported limitations implied

from the Constitution’s structure and the conflicting

rights of States. Pet. Br. at 22–29; Ala. Br. at 3–6. Under this Court’s precedent, that alone is fatal to their

theory, and adopting their position would represent a

radical reshaping of the preemption doctrine to allow

the judicial branch to make policy decisions that are

best left to Congress.

Theories of implied preemption, like those Petitioners advance, “undercut the principle that it is Congress rather than the courts that pre-empts state law.”

Chamber of Com. v. Whiting, 563 U.S. 582, 607 (2011)

(citing Gade v. Nat’l Solid Wastes Mgmt. Ass’n, 505

U.S. 88, 111 (1992) (Kennedy J., concurring in part

and concurring in judgment)); see also Kansas v. Garcia, 589 U.S. 191, 212 (2020) (although “[f]ederal authorities played a role . . . the possibility that federal

enforcement priorities might be upset is not enough to

provide a basis for preemption”). And while some constitutional doctrines can be derived from the Constitution’s structure, see Franchise Tax Bd. v. Hyatt, 587

U.S. 230, 247–48 (2019) (collecting examples),

preemption has never been implied solely from the

structure of the Constitution. Instead, preemption occurs—if at all—through the combination of a specific

textual basis and the Supremacy Clause.

17

Under the Constitution’s structure, the States

surrendered certain powers that they previously enjoyed as independent sovereigns. But they never surrendered the power of their residents to pursue state

common law tort claims against a private entity, and

Petitioners point to no authority that would support

such a contention. “The doctrine of the equality of

States . . . does not bar . . . remedies for local evils

which have subsequently appeared.” Nw. Austin Mun.

Utility Dist. No. One v. Holder, 557 U.S. 193, 203

(2009) (citing South Carolina v. Katzenbach, 282 U.S.

301, 328–29 (1966)).

The Tenth Amendment confirms that powers not

specifically granted to the federal government remain

with the States and the people. U.S. Const. amend. X;

see also Wyeth v. Levine, 555 U.S. 555, 584–85 (2009)

(Thomas, J., concurring) (“In accordance with the text

and structure of the Constitution, ‘[t]he powers delegated by the proposed constitution to the federal government, are few and defined’ and ‘[t]hose which are

to remain in the state governments, are numerous and

indefinite.’” (quoting The Federalist No. 45, at 237–38

(James Madison))). It would turn the system of federalism on its head to find that any tort claim that may

touch on a matter of federal interest is preempted.

Where preemption is asserted, the federal restriction or right that is alleged to conflict with state

law must stem from specific constitutional text or a

valid statute enacted by Congress. Garcia, 589 U.S. at

202. “[T]here is no federal pre-emption in vacuo, without a constitutional text or a federal statute to assert

it.” Hencely v. Fluor Corp., 146 S. Ct. 1086, 1093 (2026)

18

(quoting P.R. Dep’t of Consumer Affairs v. Isla Petroleum Corp., 485 U.S. 495, 503 (1988)).

Here, Petitioners fail to identify any specific constitutional text with preemptive effect. Instead, Petitioners variously describe the federal interest at stake

as the effect of interstate and international greenhouse gas emissions on the global climate (Pet. Br. at

I – questions presented); interstate pollution and disputes arising from such pollution (Pet. Br. at 21–22);

and regulation of air and water in their ambient aspects (Pet. Br. at 21). Petitioners then rely on cases

involving suits brought to regulate pollution issuing

from another State, for which the Court originally developed a body of federal common law, to argue that

Boulder’s claims are preempted. Pet. Br. at 24–25 (citing, among others, Missouri v. Illinois, 180 U.S. 208

(1901); Georgia v. Tennessee Copper Co., 206 U.S. 230

(1907); Illinois v. City of Milwaukee, 406 U.S. 91

(1972); New York v. New Jersey, 256 U.S. 296 (1921)).

That reliance is misplaced. First, the early development of federal common law to regulate interstate

pollution—which has since been displaced by statute,

Am. Elec. Power Co. v. Connecticut, 564 U.S. 410, 424

(2011)—provides no constitutional basis to preempt

Boulder’s state common law claims. Second, the purpose of applying federal common law in these early

cases was to substitute for “the forcible abatement of

outside nuisances” by a sovereign, see Tennessee Copper, 206 U.S. at 237, which is not the purpose of Boulder’s claims. Boulder is seeking compensation for

harms the Petitioners caused in Boulder; it is not seeking to restrict their emissions or prevent them from

engaging in their legitimate business activities.

19

Petitioners next suggest that Boulder’s claims

should be preempted based on the impact that those

claims, if successful, might have on activity in other

States. Pet. Br. at 28. But this Court recently rejected

an “almost per se rule” that would forbid enforcement

of state laws that have the practical effect of controlling commerce outside the State. Nat’l Pork Producers

Council v. Ross, 598 U.S. 356, 374–75 (2023) (noting

that because “many (maybe most) state laws have the

‘practical effect of controlling’ extraterritorial behavior,” an almost per se rule would “cast a shadow over

laws long understood to represent valid exercises of

the States’ constitutionally reserved powers” (citation

omitted)); see also Young v. Masci, 289 U.S. 253, 259

(1933) (“[A] person acting outside the State may be

held responsible according to the law of the State for

injurious consequences within it.”).

In addition, this Court has recognized that state

claims may impose liability for out-of-state conduct

that causes in-state injuries. Franchise Tax Bd. v. Hyatt, 538 U.S. 488, 490–94 (2003) (allowing intentional

tort claim under Nevada common law to proceed

against a California state agency for conduct that had

occurred in California but caused injury in Nevada);

Ford Motor Co. v. Mont. Eighth Judicial Dist. Ct., 592

U.S. 351, 367, 371 (2021) (allowing claims under state

tort law to proceed for injury caused by vehicles that

had been originally sold and used in other states);

Keeton v. Hustler Magazine, Inc., 465 U.S. 770, 781

(1983) (When a corporation “has continuously and deliberately exploited [a State’s] market, it must reasonably anticipate being haled into [that State’s] court[s]”

to defend actions “based on” products causing injury

there.). Petitioners’ assertion of federal preemption by

20

virtue of the structure of the Constitution is inconsistent with these precedents and should be rejected.

B. A vaguely described federal interest

over interstate pollution and climate

change cannot preempt Boulder’s state

common law claims.

In the absence of any Constitutional text that

preempts Boulder’s claims, Petitioners instead rely on

a general federal interest over interstate pollution and

climate change. This is not sufficient to preempt

claims in an area traditionally occupied by the States.

Contra Pet. Br. at 24–29. A theory of preemption that

depends on a “brooding federal interest” and an “appeal[] to a judicial policy preference should never be

enough to win preemption of a state law.” Virginia

Uranium, Inc. v. Warren, 587 U.S. 761, 767 (2019).

When a field has traditionally been occupied by

the States, as it has here, there is a strong presumption—grounded in state sovereignty—that the exercise of historic state authority is not preempted. Altria

Grp., 555 U.S. at 76–77; Wyeth, 555 U.S. at 565 n.3.

Thus, courts will not find that federal law preempts

state laws that are within the field of the States’ traditional powers without a clear and manifest expression to do so grounded in the text of the Constitution

or a federal statute. City of Burbank v. Lockheed Air

Terminal Inc., 411 U.S. 624, 633 (1973). The Supremacy Clause may not be used “to elevate abstract and

unenacted legislative desires above state law.” Virginia Uranium, Inc., 587 U.S. at 778.

Here, Boulder’s specific claims of public nuisance,

private nuisance, and trespass are state law mechanisms that serve to “protect the health and safety of

21

their citizens,” see Medtronic, Inc. v. Lohr, 518 U.S.

470, 475 (1996), which are “primarily, and historically

. . . matter[s] of local concern.” Hillsborough County v.

Automated Med. Labs., Inc., 471 U.S. 707, 719 (1985);

see also Smith v. Turner, 48 U.S. 283, 357–58 (1849)

(finding that protecting people from items injurious to

their health is universally within the States’ authority, not the federal government’s).

There is no “uniquely federal interest” in the state

common law of nuisance and trespass, even when that

law might be applied to address harms related to climate change. Boulder’s claims do not attempt to “regulate interstate emissions,” Pet. Br. at 31, or “govern

the global atmosphere,” Ala. Br. at 16. Rather, Boulder’s common law claims focus on Petitioners allegedly

misleading the public about the role of fossil fuels in

contributing to climate change and the specific harms

they assert Petitioners knowingly caused to Boulder

through their sale and production of fossil fuels. Pet.

App. 2a, 3a. Thus, Boulder’s claims of nuisance and

trespass are firmly in the realm of traditional state authority. And generally, “the State’s interest in fashioning its own rules of tort law is paramount to any

discernible federal interest.” PruneYard Shopping

Centers v. Robbins, 447 U.S. 74, 92 (1980) (Marshall,

J., concurring) (citation omitted).

Next, there are only “a few areas, involving

‘uniquely federal interests’ [that] are so committed by

the Constitution and laws of the United States to federal control that state law is pre-empted.” Hencely,

146 S. Ct. at 1094 (quoting Texas Indus., Inc. v. Radcliff Materials, Inc., 451 U.S. 630, 640 (1981)). This

Court has noted that these areas of uniquely federal

22

interest are “rare,” and emphasized the “narrowness

of this doctrine.” Id. Examples of uniquely federal interests this Court has recognized include civil liability

arising out of the performance of federal procurement

contracts, Boyle v. United Techs. Corp., 487 U.S. 500

(1988), fraud on a federal agency, Buckman Co. v.

Plantiffs’ Legal Comm., 531 U.S. 341 (2001), certain

regulation of maritime vessels, United States v. Locke,

529 U.S. 89 (2000), and patent law, Bonito Boats Inc.

v. Thunder Craft Boats Inc., 489 U.S. 141 (1989).

While Petitioners and several amici have posited

that interstate pollution is a unique area of federal

concern, there is no recognized area of federal common

law for claims like Boulder’s. Before the Clean Air Act

and the Clean Water Act displaced the federal common law of interstate pollution, federal courts recognized “federal common-law suits brought by one State

to abate pollution emanating from another State.” Am.

Elec. Power Co., 564 U.S. at 421. Boulder’s claims for

compensation do not fit within that line of precedent.

Petitioners are also incorrect that the Clean Air

Act preempts Boulder’s claims. Even if Boulder’s

claims sought to regulate air pollution (which they do

not), the Clean Air Act has never been understood to

comprehensively occupy the field of emissions regulation for any pollutant. See North Carolina, ex rel.

Cooper v. Tenn. Valley Auth., 615 F.3d 291, 302 (4th

Cir. 2010) (“We need not hold flatly that Congress has

entirely preempted the field of emissions regulation.”).

In the Clean Air Act, Congress addressed the federal

interests in interstate pollution through a system of

cooperative federalism that reserves a robust role for

23

the States. This Court has determined, when interpreting the materially identical savings clauses of the

Clean Water Act, that those clauses “negate[] the inference that Congress ‘left no room’ for state causes of

action,” Int’l Paper Co. v. Ouellette, 479 U.S. 481, 492

(1987); see also Am. Elec. Power Co., 564 U.S. at 429

(recognizing that state tort remedies may be available

if not preempted by the Clean Air Act). Indeed, instead

of boxing States out, the Clean Air Act makes “the

States and the Federal Government partners in the

struggle against air pollution.” Gen. Motors Corp. v.

United States, 496 U.S. 530, 532 (1990). 4 Petitioners

have given this Court no reason to believe that Congress’ judgment as to the nature and scope of the federal interests in interstate air pollution, and the

impact of state common law on those interests, was incorrect. And thus, Petitioners have provided no reason

for the Court to rule that Boulder’s claims are constitutionally preempted.

But even if the Constitution required the Court to

second-guess Congress’s judgment as to the federal interests in interstate pollution, Petitioners would need

to establish a significant conflict between that interest

and Boulder’s claims. Hencely, 146 S. Ct. at 1094 (“the

identification of a uniquely federal interest ‘does not

. . . end the inquiry’ . . . this Court’s precedents require

4 The United States’ thin assurance of comprehensive, and ex-

clusive, federal regulation, U.S. Br. 34, n.4, flouts the cooperative

federalism framework and cannot be squared with the U.S. Environmental Protection Agency’s recent efforts to disclaim legal

authority or intent to regulate the vast majority of domestic

greenhouse gas emissions from both mobile and stationary

sources, 91 Fed. Reg. 7686 (Feb. 18, 2026); 90 Fed. Reg. 25784,

25792 (June 17, 2025).

24

‘a significant conflict . . . between an identifiable federal policy or interest and the operation of state law.’”

(quoting Boyle, 487 U.S. at 507)). Mere overlap between state and federal law is not enough. Boyle, 487

U.S. at 509 (“the state-imposed duty of care that is the

asserted basis of [] liability . . . is precisely contrary to

the duty imposed by the Government contract . . . .

Even in this sort of situation, it would be unreasonable

to say that there is always a ‘significant conflict’ between the state law and a federal policy or interest.”

(internal quotations omitted)).

Rather, the Court has found state law impliedly

preempted only where “it is impossible for a private

party to comply with both state and federal requirements, or where state law stands as an obstacle to the

accomplishment and execution of the full purposes

and objectives of Congress.” Freightliner Corp. v. Myrick, 514 U.S. 280, 287 (1995) (quotations omitted).

This is a high threshold to clear. See Wyeth, 555 U.S.

at 581 (in the context of both state and federal laws

about the contents of drug labels, finding that state

law was not preempted because it was possible for the

company to label their drugs in a way that complied

with both federal and state laws). 5

5 This Court’s recent decision in Monsanto Company v. Durnell,

146 S. Ct. 2001 (2026), found that a common law failure to warn

claim was preempted because the Federal Insecticide, Fungicide,

and Rodenticide Act (“FIFRA”) expressly preempts States from

imposing labeling requirements that are in addition to or different from those under FIFRA, and the common law claims at issue

were directly premised on such requirements. Because that matter involved express preemption, it has no bearing on Petitioners’

argument for preemption based on the Constitution’s structure.

25

None of the traditional preemption tests can be

satisfied simply by examining the structure of the

Constitution. Accordingly, the Constitution’s structure alone does not provide a concrete federal interest

sufficient to overcome the presumption against

preemption of traditional state authority embodied in

tort law.

C. Petitioners’ theory would usurp the role

of state legislatures and state courts in

policing the bounds of common law

claims to protect both businesses and

state residents.

Tort law has developed via case law and statutory

changes. The give-and-take between state legislatures

and state courts reflects policy judgments made within

local communities—guided by local courts, local

norms, and local expectations. Dobbs et al., The Law

of Torts, § 19. Boulder’s attempt to hold fossil fuel companies accountable in tort for their alleged harms is in

line with that tradition.

Emphasizing the primacy of their sovereign authority in this area, States have historically determined whether to shield or prosecute corporate actors

who commit torts against their residents or territory.

Wos v. E.M.A. ex rel. Johnson, 568 U.S. 627, 652 (2013)

(Roberts, C.J., dissenting) (recognizing that “States

define the contours of their own tort law all the time,

setting rules about who may recover in particular circumstances, what claims may be alleged, which parties are liable, what defenses may be asserted, what

damages are recoverable, and so on.”).

26

In that tradition, state elected officials charged

with balancing economic interests and the public welfare can shield entities from state tort liability when

they deem it appropriate. See Heidi L. Feldman, From

Liability Shields to Democratic Theory: What We Need

from Tort Theory Now, 14 J. Tort L. 373, 383–84

(2021) (listing many different types of protections

States have created that limit or eliminate a defendant’s potential liability, such as restrictions on

grounds of liability for nonmanufacturer sellers, caps

on punitive damages and restrictions on medical malpractice liability). 6

Conversely, state common law tort claims serve

an important role in protecting States and their residents from harmful behavior, including by holding private businesses accountable for injuries inflicted

within those States. For example, since the early

2000s, thousands of lawsuits have been brought

against pharmaceutical corporations operating in various parts of the opioid supply chain under common

law theories like public nuisance and negligence. 7

6 State laws protecting defendants who complied with public

health guidance during the COVID-19 pandemic are a recent example. See, e.g., Ala. Code § 6-5-792(a)–(b) (2021); H.B. 76, 32d

Leg. (Alaska 2021); Fla. Stat. Ann. § 768.38(3)(c)2 (2021); Iowa

Code Ann. § 686D.5 (2020); Kan. Stat. Ann. § 60-5504 (2020); La.

Stat. Ann. § 9:2800.25 (2020); Mich. Comp. Laws § 691.1455

(2020); Miss. Code Ann. § 11-71-5 (2020); Legis. B. 39(3), 107th

Leg., 1st Sess. (Neb. 2021); Nev. Rev. Stat. § 41.835(1)(b)(1)

(2020); Okla. Stat. tit. 76, § 111(B) (2021).

7 See Valerie Bauman, States, Cities Eye $26 Billion Deal: Opi-

oid Litigation Explained, Bloomberg L. (July 26, 2021),

https://news.bloomberglaw.com/health-law-and-business/states-

27

These lawsuits alleged specific conduct regarding the

industry’s distribution scheme that caused sales of

opioids to skyrocket, resulting in devastating harm in

communities around the country. 8

Similarly, state public nuisance claims were at

the “heart of litigation against tobacco companies in

the 1990s, resulting in . . . one of the most significant

settlement agreements in American product liability

jurisprudence.” Michael J. Purcell, Settling High: A

Common Law Public Nuisance Response to the Opioid

Epidemic, 52 Colum. J.L. & Soc. Probs. 135, 136

(2018)). 9 The scope of potential liability and the size of

the potential monetary award in those cases was not

a basis to bar litigants from the courthouse door. Ra-

cities-eye-26-billion-deal-opioid-litigation-explained (on file with

the Colorado Attorney General’s Office).

See e.g., In re Nat’l Prescription Opiate Litigation, 477 F.

Supp. 3d 613, 617 (N.D. Ohio 2020); Geoff Mulvihill & John

Seewer, Purdue Pharma, US States Agree to New Opioid Settlement, Assoc. Press (Mar. 3, 2022), https://apnews.com/article/purdue-pharma-opioidsettlement9482fa0389f68de6844d13ea2ebefe5a; Jan Hoffman,

Drug Distributors and J.&J. Reach $26 Billion Deal to End Opioid Lawsuits, N.Y. Times (Nov. 11, 2021),https://www.nytimes.com/2021/07/21/health/opioids-distributorssettlement.html#:~:text=After%20nearly%20two%20years%20of,health%20crisis%20that%20has%20killed (both on file with the Colorado

Attorney General’s Office).

8

9 Many such cases involved claims that the tobacco industry

withheld data showing the health risks posed to consumers of

their products. See In re Tobacco II Cases, 207 P.3d 20, 27 (Cal.

2009) (reviewing allegations that defendants misled consumers

about health risks of smoking through deceptive advertising).

28

ther, arguments from the tobacco industry that employment and economic consequences would follow if

tort liability was imposed were expressly rejected. See

Cipollone v. Liggett Group, Inc., 644 F. Supp. 283, 289

(D.N.J. 1986) (“[W]hile it may be the case that the legislative branch has formulated some policies which favor the cigarette industry, defendants have identified

no other provision in the federal law which so favors

that industry that it directly prohibit[s] states from

enforcing those laws which protect the health and

safety of their citizens in any way which might affect

the profitability of cigarette sales.”).

Other notable examples of state tort laws’ integral

role in holding national and international corporations accountable include state common law tort

claims against the asbestos and lead-based paint industries. See, e.g., Borel v. Fibreboard Paper Prods.

Corp., 493 F.2d 1076, 1103 (5th Cir. 1973) (affirming

finding that manufacturers of insulation materials

containing asbestos were liable for damages under

Texas tort law); Lockwood v. AC & S, Inc., 744 P.2d

605 (Wash. 1987) (affirming that asbestos manufacturers were liable under negligence and strict liability

theories); Beraglia v. Owens-Corning Fiberglass

Corp., 606 So. 2d 1213, 1215 (Fla. Ct. App. 1992) (allowing plaintiffs to proceed with strict liability claim

under state common law against asbestos manufacturer.); People v. ConAgra Grocery Prods. Co., 17 Cal.

App. 5th 51, 65, 161 (Ct. App. 2017) (allowing public

nuisance action under state common law against manufacturers of lead-based paint for affirmatively promoting lead paint for interior use with knowledge of

the hazard that such use would create).

29

These examples underscore the traditional role of

state tort law in holding large corporations accountable when they inflict broad-based harms on States and

their residents. State legislatures and courts, who represent and are directly accountable to those experiencing such harms, are best positioned to regulate the

bounds of state tort law. Yet here, Petitioners ask to

be excused from potential liability for their actions

based on implications they would read into the Constitution, not its text. Such a sweeping, judge-made policy is inconsistent with this Court’s jurisprudence,

intrudes on state sovereignty, and would permit large

tortfeasors to escape state tort liability when their actions cause tangible harm. The Court should not countenance such an expansive invasion of traditional

state authority based on nothing more than the vague

and brooding federal interest Petitioners purport to

find in the Constitution’s structure.

CONCLUSION

Amici States respectfully request that the Court

dismiss this case for lack of jurisdiction or, alternatively, affirm the Colorado Supreme Court’s decision.

30

Respectfully submitted,

PHILIP J. WEISER

Attorney General

State of Colorado

ROB BONTA

Attorney General

State of California

RUSSELL D. JOHNSON

Deputy Solicitor General

Counsel of Record

SAMUEL T. HARBOURT

Solicitor General

CARRIE E. NOTEBOOM

LAURA J. ZUCKERMAN

Assistant Deputy Attorney Supervising Deputy AtGeneral

torney General

IAN FEIN

ROBYN WILLE

First Assistant Attorney

Deputy Solicitor General

General

HEATHER M. LEWIS

BRIAN CALAVAN

CORY HALLER

Senior Assistant Attorney Deputy Attorneys

General

General

GABBY FALCON

Assistant Attorney General 1300 I St.

CAMERON BONNELL

Sacramento, CA 95814

Assistant Attorney General

Fellow

1300 Broadway, 10th Floor

Denver, Colorado 80203

Russell.Johnson@coag.gov

(720) 508-6000

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31

KRIS MAYES

Attorney General

State of Arizona

2005 N. Central Ave.

Phoenix, AZ 85004

WILLIAM TONG

Attorney General

State of Connecticut

165 Capitol Ave.

Hartford, CT 06106

KATHLEEN JENNINGS

Attorney General

State of Delaware

820 N. French St.

Wilmington, DE 19801

BRIAN L. SCHWALB

Attorney General

District of Columbia

400 6th St. NW

Washington, DC 20001

ANNE E. LOPEZ

Attorney General

State of Hawai‘i

425 Queen St.

Honolulu, HI 96813

KWAME RAOUL

Attorney General

State of Illinois

115 S. LaSalle St.

Chicago, IL 60602

AARON M. FREY

Attorney General

State of Maine

6 State House Station

Augusta, ME 04333

ANTHONY G. BROWN

Attorney General

State of Maryland

200 Saint Paul Pl.

Baltimore, MD 21202

ANDREA JOY CAMPBELL

Attorney General

Commonwealth of Massachusetts

One Ashburton Pl.

Boston, MA 02108

DANA NESSEL

Attorney General

State of Michigan

P.O. Box 30212

Lansing, MI 48909

32

AARON D. FORD

Attorney General

State of Nevada

100 N. Carson St.

Carson City, NV 89701

JENNIFER DAVENPORT

Attorney General

State of New Jersey

25 Market St., 8th Fl.

Trenton, NJ 08625

LETITIA A. JAMES

Attorney General

State of New York

28 Liberty St.

New York, NY 10005

DAN RAYFIELD

Attorney General

State of Oregon

1162 Court St. NE

Salem, OR 97301

PETER F. NERONHA

Attorney General

State of Rhode Island

150 S. Main St.

Providence, RI 02903

CHARITY R. CLARK

Attorney General

State of Vermont

109 State St.

Montpelier, VT 05609

NICHOLAS W. BROWN

Attorney General

State of Washington

P.O. Box 40100

Olympia, WA 98504

August 3, 2026