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

Supreme Court briefMay 21, 2026

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No. 25-170

In the Supreme Court of the United States

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

COUNTY COMMISSIONERS OF BOULDER COUNTY, ET AL.

On Writ of Certiorari to

the Supreme Court of Colorado

BRIEF OF AMICUS CURIAE

PROTECT THE FIRST FOUNDATION

SUPPORTING PETITIONERS AND REVERSAL

GENE C. SCHAERR

Counsel of Record

ERIK S. JAFFE

BRIAN J. FIELD

HANNAH C. SMITH

JOSHUA J. PRINCE

SCHAERR | JAFFE LLP

1717 K Street NW, Suite 900

Washington, DC 20006

Telephone: (202) 787-1060

gschaerr@schaerr-jaffe.com

Counsel for Amicus Curiae

MAY 21, 2026

QUESTIONS PRESENTED

1. Whether federal law precludes state-law

claims seeking relief for injuries allegedly caused by

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

2. Whether this court has statutory and Article

III jurisdiction to hear this case.

TABLE OF CONTENTS

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

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

INTRODUCTION, SUMMARY, AND

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

STATEMENT .............................................................. 3

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

II.

Allowing Broad State Tort Law to

Punish Corporate Speech Impermissibly

Burdens Constitutionally Protected

Activity. ........................................................... 4

The First Amendment

presumptively forbids

discrimination against content,

viewpoints, or classes of speakers. ......... 4

Respondents’ state-law tort theories

would make fossil fuel

manufacturers liable because of

who they are and the disfavored

messages they convey. ............................ 7

Respondents’ State-Law Tort Theories

Punish Protected Petitioning Activities

Directed at the Public and Their

Representatives. ............................................. 9

The Petition Clause protects efforts

to influence the public and the

government alike..................................... 9

iii

Petitioners’ speech involves efforts

to influence the public and the

government. ........................................... 12

III. Allowing Respondents’ State-Law

Claims Would Produce Absurd and

Dangerous Results That Would

Undermine Democratic Debate and

Scientific Progress. ....................................... 15

History shows that our

understanding of the natural world

often entails reversal of previously

settled views. ......................................... 15

Using the courts to impose liability

on commercial entities that

challenge current scientific

understandings would dangerously

impede scientific progress. .................... 20

CONCLUSION .......................................................... 22

TABLE OF AUTHORITIES

Cases

Abrams v. United States,

250 U.S. 616 (1919) ................................................ 20

Allied Tube & Conduit Corp. v. Indian

Head, Inc., 486 U.S. 492 (1988) ........................ 10-12

American Commc’ns Ass’n, C.I.O. v. Douds,

339 U.S. 382 (1950) ................................................ 19

Barr v. American Ass’n of Pol.

Consultants, Inc., 591 U.S. 610 (2020) .................... 5

BE&K Construction Co. v. NLRB,

536 U.S. 516 (2002) ................................................ 11

Bill Johnson’s Rests., Inc. v. NLRB,

461 U.S. 731 (1983) .......................................... 11, 13

Brown v. Board of Educ.,

347 U.S. 483 (1954) ................................................ 18

Buckley v. Valeo,

424 U.S. 1 (1976) .................................................. 6, 8

California Motor Transp. Co. v. Trucking

Unltd., 404 U.S. 508 (1972) ................................... 10

Chiles v. Salazar,

146 S. Ct. 1010 (2026) ...................................... 15, 18

Citizens United v. FEC,

558 U.S. 310 (2010) .............................................. 5, 8

Daubert v. Merrell Dow Pharms., Inc.,

509 U.S. 579 (1993) .......................................... 15, 16

Eastern R.R. Presidents Conf. v.

Noerr Motor Freight, Inc.,

365 U.S. 127 (1961) ..................................... 10-12, 15

First Nat’l Bank of Bos. v. Bellotti,

435 U.S. 765 (1978) .................................................. 9

Graham v. Florida,

560 U.S. 48 (2010) .................................................. 19

Hall v. Florida,

572 U.S. 701 (2014) ................................................ 16

Iancu v. Brunetti,

588 U.S. 388 (2019) .................................................. 4

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

& Mun. Emps., 585 U.S. 878 (2018)........................ 2

Massachusetts v. EPA,

549 U.S. 497 (2007) ................................................ 21

McCrory v. Alabama,

144 S. Ct. 2483 (2024) ............................................ 19

Members of City Council of L.A. v. Taxpayers

for Vincent, 466 U.S. 789 (1984) .............................. 6

National Rev., Inc. v. Mann,

589 U.S. 1088 (2019) .............................................. 22

Obergefell v. Hodges,

576 U.S. 644 (2015) ................................................ 18

Roper v. Simmons,

543 U.S. 551 (2005) ................................................ 19

Rosenberger v. Rector & Visitors of

Univ. of Va., 515 U.S. 819 (1995) ......................... 4-6

Sorrell v. IMS Health Inc.,

564 U.S. 552 (2011) .................................................. 6

Sosa v. DIRECTV, Inc.,

437 F.3d 923 (9th Cir. 2006) .................................. 11

Stanford v. Kentucky,

492 U.S. 361 (1989) ................................................ 18

Thomas v. Collins,

323 U.S. 516 (1945) .............................................. 6, 9

Turner Broad. Sys., Inc. v. FCC,

512 U.S. 622 (1994) .............................................. 6, 8

United Mine Workers of Am. v. Pennington,

381 U.S. 657 (1965) .......................................... 10, 12

Whitney v. California,

274 U.S. 357 (1927) ................................................ 14

Whole Woman’s Health v. Paxton,

10 F.4th 430 (5th Cir. 2021) ............................ 16, 17

Constitutional Provision

U.S. Const. amend. I ................................................... 4

Regulation

68 Fed. Reg. 52930 .................................................... 21

Other Authorities

Amicus Brief of Roger Pielke, Jr.,

Lighthiser v. Trump, No. 25-6714

(9th Cir. Mar. 5, 2026), ECF No. 77 ...................... 14

Isaac Asimov,

How Did We Find Out the Earth Is Round

(1972) ...................................................................... 17

vii

Nistha R. Dash et al.,

Dr. Ignaz Phillip Semmelweis: The

Unrecognized Pioneer of Aseptic Practices,

16 Cureus e68350 (2024) ....................................... 16

Brady Dennis,

Scientists now say this worst-case

climate scenario is ‘implausible.’

Here’s what it means., Wash. Post

(May 19, 2026, 5:00 AM EDT) ............................... 19

Fed. Jud. Ctr.,

Reference Manual on Scientific Evidence

(2000) ...................................................................... 18

Intergovernmental Panel on Climate Change,

Climate Change Information for Regional

Impact and for Risk Assessment, in

Climate Change 2021: The Physical Science

Basis (2021) ............................................................ 14

Les Lang,

Gastroenterology News: Barry Marshall

2005 Nobel Laureate in Medicine and

Physiology, 129 Gastroenterology 1813

(2005) ...................................................................... 17

Nat’l Rsch. Council,

Climate Change Science: An Analysis

of Some Key Questions (2001) ................................ 21

The Kyoto Protocol,

United Nations Climate Change ........................... 13

INTRODUCTION, SUMMARY, AND

INTEREST OF AMICUS CURIAE 1

This case is about more than federal preemption,

climate change, or fossil fuels. It is about whether the

First Amendment still protects the right of all

Americans—including those who produce and sell the

energy that powers our economy—to speak and

petition on matters of urgent public concern. While

Respondents seek to impose billions of dollars in tort

liability on Petitioners for extracting, refining, or

selling fossil fuels, they also seek to punish what

Petitioners said about those activities and their effect

on climate change—in public statements, through

advertisements, and while petitioning.

But those efforts are foreclosed by the First

Amendment. Through their speech, Petitioners

contributed to the national debate over climate science

and the Nation’s energy policy. By treating protected

expression as a tortious cause of distant future harms,

Respondents would convert the courtroom into a

forum for punishing one side of an ongoing scientific

controversy. Whatever the merits of the questions

presented, constitutional-avoidance principles should

lead this Court to hold that the First Amendment

forbids Respondents’ theories.

After all, as this Court has recognized, “climate

change” is a “sensitive political topic[]” “of profound

value and concern to the public.” Janus v. American

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

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

members or counsel, has made a monetary contribution toward

the brief’s preparation or submission.

Fed’n of State, Cnty., & Mun. Emps., 585 U.S. 878,

913-914 (2018) (cleaned up). Speech about climate

change thus “occupies the highest rung of the

hierarchy of First Amendment values and merits

special protection.” Ibid. (cleaned up). Accordingly, for

Respondents’ theories to prevail, this Court would

have to deprive Petitioners’ speech of the “special”

protection to which it is entitled.

This case is particularly troubling to amicus

Protect the First Foundation (PT1)—a nonprofit,

nonpartisan organization that advocates for

protecting First Amendment rights. That is because

Respondents’ novel tort theories seek to punish, and

thereby chill, core political and commercial expression

and association on this important issue. While

Petitioners have shown (at 21-47) that Respondents’

claims are federally preempted, PT1 writes separately

to highlight the additional threat Respondents’

theories pose to Petitioners’ protected speech,

petitioning activities, and association—including

advocacy both to government officials and to the

public: Allowing Respondents’ theories to proceed

would undermine a core function of public debate, as

illustrated by examples of scientists who successfully

challenged—often at great personal and professional

risk—then-prevailing scientific dogmas. As with these

earlier scientists, if opponents of popular viewpoints

on issues like climate change are silenced or punished

for their views, that will stunt scientific advancement.

And it will harm efforts to improve our understanding

of the natural world and to formulate sound policy

responses to natural phenomena.

The decision below should be reversed.

STATEMENT

Petitioners produce and sell “fossil fuels around

the world.” Pet.5. Respondents brought a host of statelaw claims against Petitioners, all of which turn on the

allegation that Petitioners furthered the “unchecked

production, promotion, refining, marketing and sale of

fossil fuels” throughout the world and thereby “led to

unchecked fossil fuel use” and increased “the

concentration of greenhouse gases * * * in the

atmosphere.” J.A.3, ¶7. They then claimed that

increased greenhouse gases have caused “global

average temperatures” to rise, J.A.37, ¶134, leading to

“larger and more frequent wildfires, increased

concentrations of ground-level ozone, higher

transmission of viruses and disease from insects,

altered streamflows, bark beetle outbreaks, ecosystem

damage, forest die-off, reduced snowpack, and

drought” in Colorado. J.A.39, ¶140.

Petitioners moved to dismiss, claiming that

Respondents impermissibly sought to punish them for

having “taken or supported positions” on climate

change “that are contrary to” Respondents’ views.

Defs.’ Dist. Ct. Mot. to Dismiss 20. The district court

rejected that defense on the dubious premise that

Petitioners’ misleading “commercial” speech is not

protected. App.114a. And since Respondents “allege

that the speech in question was misleading,” to the

district court, that ended the inquiry. Ibid.

The Colorado Supreme Court did not address the

First Amendment.

ARGUMENT

Allowing Broad State Tort Law to Punish

Corporate Speech Impermissibly Burdens

Constitutionally Protected Activity.

Petitioner’s preemption theories provide an

independent reason to reverse the decision below. See

Pet. Br. 21-47. But this Court should also reverse as a

matter of constitutional avoidance because of the First

Amendment harms that would inevitably arise from

allowing Boulder County’s viewpoint-, content-, and

speaker-discriminatory state-law tort claims to

proceed.

The First Amendment presumptively

forbids discrimination against content,

viewpoints, or classes of speakers.

The First Amendment expressly forbids the

government from taking any actions that “abridg[e]

the freedom of speech.” U.S. Const. amend. I.

1. And one “core postulate of free speech law” is

that the “government may not discriminate against

speech based on the ideas or opinions it conveys.”

Iancu v. Brunetti, 588 U.S. 388, 393 (2019).

Such unlawful discrimination can come in many

forms. Often, governments will try to “regulate speech

based on its substantive content or the message it

conveys.” Rosenberger v. Rector & Visitors of Univ. of

Va., 515 U.S. 819, 828 (1995). Other times, the

government engages in an “all the more blatant”

“violation of the First Amendment” by “target[ing] not

subject matter, but particular views taken by speakers

on a subject.” Id. at 829. Such “[v]iewpoint

discrimination” is “presumptively unconstitutional”

because it represents a particularly “egregious form of

content discrimination.” Id. at 829-830.

But the First Amendment also forbids less blatant

forms of discrimination. For example, this Court treats

government action as impermissibly content-based if

it imposes “[s]peech restrictions based on the identity

of the speaker.” Citizens United v. FEC, 558 U.S. 310,

340 (2010). Speaker-based restrictions, after all, “are

all too often simply a means to control content.” Ibid.

Given the blurriness of the line between speakerand content-based discrimination, the Court has held

that the “First Amendment protects speech and

speaker, and the ideas that flow from each.” Id. at 341.

This makes sense. The public too has a “right and

privilege to determine for itself what speech and

speakers are worthy of consideration.” Ibid.

Further, as Justice Gorsuch has explained, “the

First Amendment does its real work in giving voice to

those a majority would silence.” Barr v. American

Ass’n of Pol. Consultants, Inc., 591 U.S. 610, 649-650

(2020) (Gorsuch, J., concurring in the judgment in part

and dissenting in part). That is because “a

constitutional right would hardly be needed to protect

popular speakers” or—for that matter—popular

opinions. Id. at 649-650. Rather than allow the

government to discriminate against unpopular

speakers for the message they convey, this Court has

held that “speaker-based laws demand strict scrutiny

when they reflect the Government’s preference for the

substance of what the favored speakers have to say (or

aversion to what the disfavored speakers have to say).”

Turner Broad. Sys., Inc. v. FCC, 512 U.S. 622, 658

(1994).

2. This Court’s caselaw abounds with examples of

unconstitutional governmental attempts to “favor one

speaker over another” based on the message she

conveys. Rosenberger, 515 U.S. at 828 (citing Members

of City Council of L.A. v. Taxpayers for Vincent, 466

U.S. 789, 804 (1984)). In Buckley v. Valeo, 424 U.S. 1

(1976) (per curiam), for example, the Court

invalidated an expenditure limit “designed to ensure

that the political speech of the wealthy not drown out

the speech of others”—an aim necessarily “concerned

with the communicative impact of the regulated

speech.” Turner Broad. Sys., 512 U.S. at 658

(discussing Buckley). Similarly, in Sorrell v. IMS

Health Inc., the Court invalidated a Vermont law that

“restrict[ed] the sale, disclosure, and use of pharmacy

records that reveal the prescribing practices of

individual doctors” “for marketing purposes” by

pharmaceutical manufacturers. 564 U.S. 552, 557

(2011). The Court found that the law facially

“burden[ed] disfavored speech by disfavored speakers”

because it disfavored both “marketing, that is, speech

with a particular content” and “specific speakers,

namely pharmaceutical manufacturers.” Id. at 564.

And in Thomas v. Collins, the Court held that

“employers’ attempts to persuade to action with

respect to joining or not joining unions are within the

First Amendment’s guaranty” just as much as “the

employees’ converse right.” 323 U.S. 516, 537-538

(1945).

As explained next, these precedents make quick

work of Respondents’ state-law tort theories since they

embody precisely

discrimination.

these

forbidden

forms

Respondents’ state-law tort theories

would make fossil fuel manufacturers

liable because of who they are and the

disfavored messages they convey.

As to those: Respondents argued in opposing

certiorari that their claims are “based on two distinct

theories of liability.” BIO 3. The first challenges

Petitioners’ advertising, which Respondents claim,

“misled the public about the impacts of climate change

and the role” that “fossil fuel products have played in

exacerbating those impacts.” Ibid. (quoting App.3a).

The second challenges Petitioners “promoting,”

“marketing[,] and selling fossil fuels.” Ibid. (quoting

App.2a).

1. Central to Respondents’ theories is the

repeated claim that Petitioners engaged in “unchecked

fossil fuel activities”—a term that Respondents

defined to include the “promotion” and “marketing” of

fossil fuels—“without disclosing” or by downplaying

what Respondents believe to be “the climate-altering

dangers * * * associated with the use of fossil fuels.”

J.A.3, ¶7; J.A.5, ¶14; J.A.104-105, ¶¶407-411.

These theories are dripping with textbook

speaker-based discrimination. Respondents have

singled out Petitioners—fossil-fuel producers and

sellers—and seek to impose on them special burdens

that no other industry, environmental group, or

renewable-energy advocate faces. Indeed, even other

groups that engage in discussions about the effects of

fossil fuels, such as climate-based non-profits, are

ignored. The reason is simple: Such groups espouse

the correct view—at least to Respondents. Thus, the

risk that speaker-based discrimination is just “a

means to control content,” Citizens United, 558 U.S. at

340, has materialized here.

The conclusion that Respondents seek to punish

Petitioners because of who they are and the message

they are promoting is unavoidable. While Respondents

sheepishly disclaim any effort to “impose liability,

restrain or interfere with [Petitioners’] ability to

participate in public debates about climate change, or

otherwise interfere with [Petitioners’] speech,”

J.A.139, ¶541, there can be no question that

Respondents are, like the government in Buckley,

primarily “concerned with the communicative impact”

of Petitioners’ speech. Turner Broad. Sys., 512 U.S. at

658 (discussing Buckley).

Elsewhere

the

Amended

Complaint

Respondents say as much. See J.A.1-139. They claim,

for example, that Petitioners were so persuasive in

their advocacy efforts that it caused “uncertainty in

the minds of the American public” about whether fossil

fuels caused climate change. J.A.111, ¶436. And that

is the only reason for this case. If Petitioners agreed

with Respondents that fossil fuels cause climate

change, Respondents would not have brought this case

at all. Respondents’ theories, then, are infected with

impermissible viewpoint discrimination too.

2. In short, while this Court can reject

Respondents’ theories for the reasons Petitioner

identifies, it should do so with an eye towards the First

Amendment harms that would follow if Respondents’

claims were to proceed. For decades, this Court has

emphasized that the “inherent worth of * * * speech in

terms of its capacity for informing the public does not

depend upon the identity of its source, whether

corporation, association, union, or individual.” First

Nat’l Bank of Bos. v. Bellotti, 435 U.S. 765, 777 (1978).

And it has recognized that the First Amendment

protects “the opportunity to persuade to action, not

merely to describe facts.” Thomas, 323 U.S. at 537.

The Court should do so again here. All that

Petitioners sought to do through their speech is to

promote a viewpoint that Respondents disfavor. And

Respondents’ efforts to retroactively declare the other

side of this scientific and policy debate “misleading”—

and therefore actionable—should be held foreclosed by

the First Amendment.

II. Respondents’ State-Law Tort Theories

Punish Protected Petitioning Activities

Directed at the Public and Their

Representatives.

Since Respondents seek to punish Petitioners’

efforts to influence public perception and public policy

regarding fossil fuels, their theories should also be

rejected for punishing core First Amendmentprotected petitioning activities.

The Petition Clause protects efforts to

influence the public and the

government alike.

This Court has long recognized that, in our

representative democracy, “the whole concept of

representation depends upon the ability of the people

to make their wishes known to their representatives.”

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

Inc., 365 U.S. 127, 137-138 (1961); accord United Mine

Workers of Am. v. Pennington, 381 U.S. 657, 669-670

(1965). The “right of petition is one of the freedoms”

that makes this possible. Noerr, 365 U.S. at 138.

1. Consistent with that protection, this Court has

held that “mere attempts to influence the Legislative

Branch for the passage of laws or the Executive

Branch for their enforcement” are protected by the

First Amendment’s Petition Clause. California Motor

Transp. Co. v. Trucking Unltd., 404 U.S. 508, 510

(1972) (discussing Noerr). The Court later recognized

that this doctrine—known as the Noerr-Pennington

doctrine—extended “the right to petition” to “all

departments of the Government,” including to

“administrative agencies (which are both creatures of

the legislature, and arms of the executive) and to

courts, the third branch of Government.” Ibid.

But the Court has also recognized that the right

to petition as applied in Noerr-Pennington extends to

advocacy directed at the public. In Allied Tube &

Conduit Corp. v. Indian Head, Inc., for example, the

Court explained that “[a] publicity campaign directed

at the general public, seeking legislation or executive

action” also “enjoys * * * immunity.” 486 U.S. 492, 499

(1988). This was nothing new. In Noerr itself, this

Court refused to impose statutory liability both for the

defendants’ efforts to “obtain legislation,” and for their

efforts to alter “the goodwill of * * * the public

generally.” Noerr, 365 U.S. at 142. In so holding, the

Court recognized that the petitioning right protects

against liability for harms that come as an “incidental

effect of * * * an attempt * * * to influence legislation

by a campaign of publicity.” Id. at 143.

2. At first, the Noerr-Pennington doctrine applied

largely in the antitrust space to afford companies

immunity from antitrust suits challenging those

companies’ lobbying of government officials as

anticompetitive. Allied Tube, 486 U.S. at 499-500. But

this Court has since expanded the doctrine beyond

antitrust suits to grant more general “immun[ity] from

statutory liability for” all manner of “petitioning

conduct” including conduct “outside the antitrust

field.” Sosa v. DIRECTV, Inc., 437 F.3d 923, 929-930

(9th Cir. 2006) (citing Bill Johnson’s Rests., Inc. v.

NLRB, 461 U.S. 731, 741-744 (1983)). In Bill

Johnson’s Restaurants, for example, the Court,

“sensitive to the[] First Amendment values” that

undergird Noerr-Pennington in the antitrust context,

also looked to them “in construing the” National Labor

Relations Act. 461 U.S. at 741. On that basis the Court

held that an ongoing “well-founded” state lawsuit

could not be challenged as an unfair labor practice. Id.

at 743. And in BE&K Construction Co. v. NLRB, the

Court rejected a standard of the National Labor

Relations Board that would have covered “all

reasonably based but unsuccessful suits filed with a

retaliatory purpose” because, the Court held, it

violated the right to petition. 536 U.S. 516, 536-537

(2002).

Through these decisions, the Court has also made

clear that the Petition Clause’s protections are values

neutral. That is why, as the Court has explained, the

right to petition “cannot properly be made to depend

upon” the petitioner’s “intent.” Noerr, 365 U.S. at 139.

For example, in the antitrust context, the Court

has explained that a company can have an

“anticompetitive purpose” in petitioning—a purpose

that would violate the Sherman Act in any other

circumstance—and still avoid liability precisely

because the act involves petitioning. Id. at 139-140;

see also Pennington, 381 U.S. at 669. Indeed,

petitioning activity is protected “even when” a

petitioning “campaign employs unethical and

deceptive methods.” Allied Tube, 486 U.S. at 499-500.

And regardless of methodology, as explained

above, this important First Amendment protection

includes petitioning both the government itself and

the public.

Petitioners’ speech involves efforts to

influence the public and the

government.

These same foundational principles bar

Respondent’s first theory of liability since it attacks

Petitioners’ efforts to influence the government both

directly and through coordinated publicity campaigns.

Indeed, as previously explained, Respondents

argued before this Court that their first “distinct

theor[y] of liability” is that Petitioners’ ‘“advertising’”

‘“misled the public.’” BIO 3 (quoting App.3a). And

their second theory is much the same, as it challenges

Petitioners’ “marketing” and “promoting” their

products. Ibid. (quoting App.2a). Both theories are

thus based on the underlying claim that Petitioners

“acted to thwart public awareness,” J.A.106-107, ¶418,

tried to undermine “support for the Kyoto Protocol,” 2

J.A.108, ¶424, and generally opposed government

regulation of “fossil fuel activities,” J.A.112, ¶443.

These are protected activities. Merely calling them the

advertising, marketing, and promotion of products

changes nothing. All manner of otherwise-protected

Noerr-type petitioning could be described the same

way.

Worse still, Respondents explicitly connect

Petitioners’ publicity campaign to the outcomes of

legislative debates and the public’s “uncertainty”

about the “existence and causes of climate change.”

J.A.111, ¶436. To define the scope of the alleged harm,

Respondents allege that Petitioners’ campaign

“thwart[ed] attempts to prevent and mitigate the

climate change harms” and led to “years of inaction”

on fossil fuel regulation. J.A.112, ¶443; J.A.111. Thus,

part of the harm, as Respondents see it, is that

Petitioners’ public-facing arguments were persuasive.

J.A.111-112, ¶¶436-442.

Permitting successful advocacy to the public and

its representatives to serve as a basis of liability would

turn the Noerr-Pennington doctrine’s “sensitiv[ity] to

* * * First Amendment values” on its head. Bill

Johnson’s Rests., 461 U.S. at 741. Petitioners’ right to

publicly campaign for less regulation of fossil fuels

cannot be undermined by the fact that Respondents

2 The Kyoto Protocol claims to “commit[] industrialized countries

* * * to limit and reduce greenhouse gases * * * emissions in

accordance

with

agreed

individual

targets.”

The Kyoto Protocol, United Nations Climate Change,

https://tinyurl.com/ycxss22d (last visited May 17, 2026).

disagree with Petitioners’ characterization or critiques

of the “scientific consensus.” J.A.110, ¶435. 3

Moreover, Respondents’ representatives and

others had ample opportunities and their own First

Amendment rights to challenge such speech and to

petition with counter-speech. Under the First

Amendment, “the remedy to be applied is more speech,

not enforced silence.” See Whitney v. California, 274

U.S. 357, 377 (1927) (Brandeis, J., concurring),

overruled by Brandenburg v. Ohio, 395 U.S. 444

(1969).

3 In

any event, if Respondents are suggesting that there is

consensus on whether specific companies’ actions can cause

specific weather events or phenomena in particular places, their

claims are greatly exaggerated. The Intergovernmental Panel on

Climate Change (IPCC), the United Nations body for assessing

the science related to climate change, has synthesized and

reviewed the science to identify the human influence on climateimpact drivers (CID)—weather phenomena—and concluded that

it has “low confidence” that there is any human influence—one

way or another—on many such CIDs. See IPCC, Climate Change

Information for Regional Impact and for Risk Assessment, in

Climate Change 2021: The Physical Science Basis 1856 &

tbl. 12.12 (2021), https://tinyurl.com/mwu2p673. Roger Pielke,

Jr., a Senior Fellow at the American Enterprise Institute and a

professor emeritus at the University of Colorado Boulder whose

work IPCC regularly cites, recently examined IPCC’s discussion

in its 2021 report in detail. See Amicus Brief of Roger Pielke, Jr.

at 14-24, Lighthiser v. Trump, No. 25-6714 (9th Cir. Mar. 5,

2026), ECF No. 77. Guided by IPCC’s findings, Pielke concluded

that it was not “scientifically plausible to connect a small

marginal change in emissions” from support for fossil fuels “to

weather events and outcomes experienced by a single individual.”

Id. at 16. Given IPCC’s “low confidence” about the human

influence on multiple CIDs, the same conclusion would follow for

a single city or a single county like Respondents.

In a free society, in short, regulated individuals

and other entities must be able to advocate for their

interests. Noerr, 365 U.S. at 137-138. Respondents’

attempts to hold Petitioners liable for seeking to

persuade the public and government officials would

flout these foundational principles and cannot be

squared with the protections of the Petition Clause

any more than they can be squared with the First

Amendment’s protections of speech.

III. Allowing Respondents’ State-Law Claims

Would Produce Absurd and Dangerous

Results That Would Undermine Democratic

Debate and Scientific Progress.

Beyond violating multiple provisions of the First

Amendment, Respondents’ theories would also

undermine a core function and benefit of the First

Amendment. Any government enforcement of

supposed “consensus” on matters of science,

economics, or any other subject undermines not only

free speech, but also intellectual progress, by enforcing

orthodoxy and penalizing contrarian thought and

speakers who dare to challenge prevailing views.

History shows that our understanding

of the natural world often entails

reversal of previously settled views.

Even a cursory look through history shows that

scientific understanding is not static; “it evolves and

always has.” Chiles v. Salazar, 146 S. Ct. 1010, 1029

(2026). This is by design. As this Court has recognized,

“[s]cientific conclusions are subject to perpetual

revision.” Daubert v. Merrell Dow Pharms., Inc., 509

U.S. 579, 597 (1993). Indeed, the “scientific project”

only works when it is subjected to “broad and wideranging consideration of a multitude of hypotheses.”

Ibid. This means that “open debate is an essential

part” of the process. Id. at 596. And this open debate

produces real fruit. As Justice Alito has recognized,

debate sometimes leads to “changes adopted by

professional

associations”

being

subsequently

“rescinded” considering new arguments and data. Hall

v. Florida, 572 U.S. 701, 732 (2014) (Alito, J.,

dissenting).

1. History is full of such examples. In an era when

most ascribed to “miasma theory,” or the belief that

“disease was caused by bad air coming out of rotting

organic matter,” Dr. Ignaz Semmelweis pressed a

different view. 4 He showed that when a healthcare

professional in the process of delivering a baby simply

washed her hands with a chlorinated lime solution

before delivery, maternal deaths plummeted. 5 But Dr.

Semmelweis’s work was rejected by the broader

scientific community because of its “inclination to

adhere to established norms and resist new ideas that

challenge them,” a phenomenon now called—in his

honor—the “Semmelweis reflex.” 6

As Judge Ho has recognized, “[a] similar fate

befell Joseph Lister.” Whole Woman’s Health v.

Paxton, 10 F.4th 430, 466 (5th Cir. 2021) (Ho, J.,

concurring), overruled by Dobbs v. Jackson Women’s

4 Nistha

R. Dash et al., Dr. Ignaz Phillip Semmelweis: The

Unrecognized Pioneer of Aseptic Practices, 16 Cureus e68350, 1

(2024), https://tinyurl.com/4ks4bd9f.

5 Id. at 3.

6 Id. at 4.

Health Org., 597 U.S. 215 (2022). Contemporaries

responded to Lister, who challenged the prevailing

view of disease when he claimed that germs were the

cause of post-surgery infections, with “fierce

opposition, even mockery.” Ibid. Of course, we now

know that he was right. But imagine if Semmelweis or

Lister had been sued for the supposed adverse

consequences of challenging scientific consensus and

creating uncertainty regarding the dangers of

“miasma.”

Other examples abound. For example, “stress and

lifestyle” were long thought to be the main drivers

behind peptic ulcers. 7 Things changed when

Australian researchers Dr. Barry J. Marshall and Dr.

J. Robin Warren “went against conventional wisdom”

and “challenged prevailing dogmas” by conducting

experiments that ultimately proved that Helicobacter

pylori, a bacteria, primarily caused peptic ulcers. 8

Still other examples arise outside the medical

context. Although we now know, for example, that the

earth is round, “[f]ar back in ancient times, everybody

thought the earth was flat * * * because it looks flat.” 9

And while every elementary school student today

learns that the Earth rotates around the sun, that

correct understanding was once so controversial that

7 Les Lang, Gastroenterology News: Barry Marshall 2005 Nobel

Laureate in Medicine and Physiology, 129 Gastroenterology 1813

(2005).

8 Id. at 1813-1814.

9 Isaac

Asimov, How Did We Find Out the Earth Is Round 9

(1972) (emphasis added), https://tinyurl.com/479s3ae9.

“Galileo was put on trial” simply for defending it.10

The legal persecution of Galileo for his unorthodox

speech and ideas likely delayed the spread and

acceptance of what we now understand to be a more

accurate astronomical view of the earth and sun.

2. Changes in scientific understanding often

have legal consequences too. Perhaps most famously,

the Court in Brown v. Board of Education, 347 U.S.

483 (1954), looked to “modern authority” rather than

to “psychological knowledge at the time of Plessy v.

Ferguson” to conclude that “[s]eparate educational

facilities are inherently unequal.” Id. at 494-495.

Similarly, in Chiles, the Court explained that “[n]ot

long ago, many medical experts and organizations,

including the American Psychiatric Association,

considered homosexuality a mental disorder.” Chiles,

146 S. Ct. at 1028. But in Obergefell v. Hodges, this

Court looked to modern science to conclude that

“psychiatrists and others” now understand “sexual

orientation [to be] both a normal expression of human

sexuality and immutable.” 576 U.S. 644, 661 (2015).

Similarly, while the Court in Stanford v. Kentucky

found it “absurd” to think that a person under 18 was

not “mature enough to understand that murdering

another human being is profoundly wrong,” 492 U.S.

361, 374 (1989), it later looked to “developments in

psychology and brain science” showing “fundamental

differences between juvenile and adult minds” to

abrogate Stanford. Graham v. Florida, 560 U.S. 48, 68

10 Fed.

(2000).

Jud. Ctr., Reference Manual on Scientific Evidence 68

(2010) (discussing, inter alia, Roper v. Simmons, 543

U.S. 551 (2005)).

3. These cases show that courts too benefit from

robust scientific debate. This is true even though, as

Justice Sotomayor has recognized, “science” at times

“evolves slowly rather than in conclusive bursts.”

McCrory v. Alabama, 144 S. Ct. 2483, 2486 (2024)

(Sotomayor, J., respecting the denial of certiorari).

The fact that science is slow to evolve only

strengthens the dangers inherent in silencing debate

based on current consensus. A theory may be

universally accepted not because it is correct, but

because it is the best understanding currently

available. 11 As Justice Robert Jackson once

recognized, progress, including scientific progress,

“generally begins in skepticism about accepted

truths.” American Commc’ns Ass’n, C.I.O. v. Douds,

339 U.S. 382, 442 (1950) (Jackson, J., concurring and

dissenting, each in part). Thus, for scientific progress

to occur, everyone, including corporations, “must dare

to doubt what a * * * majority may most passionately

assert.” Ibid. As Justice Holmes recognized, “time has

upset many fighting faiths,” and “the ultimate good

desired is better reached by free trade in ideas” since

the “best test of truth is the power of the thought to

get itself accepted in the competition of the market.”

11 Respondents here, for example, based their claims in part on a

“high

emissions

scenario”

known

Representative

Concentration Pathways 8.5. See J.A.38, ¶137 & n.14. But the

IPCC is now retiring that protocol as “implausible.” See Brady

Dennis, Scientists now say this worst-case climate scenario is

‘implausible.’ Here’s what it means., Wash. Post (May 19, 2026,

5:00 AM EDT), https://tinyurl.com/4cev58r8.

Abrams v. United States, 250 U.S. 616, 630 (1919)

(Holmes, J., dissenting).

Using the courts to impose liability on

commercial entities that challenge

current scientific understandings

would dangerously impede scientific

progress.

By treating Petitioners’ public advocacy as

tortious “misinformation” simply because it conflicts

with what Respondents understand to be the current

prevailing view, see J.A.109, ¶428, Respondents’

claims would impede genuine scientific progress.

1. Respondents argue, for example, that

Petitioners “acted through a cadre of claimed climate

scientists, who they paid, directly or indirectly, to cast

doubt on climate science.” Id. ¶429. And they allege

that Petitioners “routinely referenced the work” of

those who challenged the view that fossil fuels cause

global warming “when casting doubt on and/or trying

to undermine public recognition of the scientific

consensus around climate change.” J.A.110, ¶435.

Relying on these other scientists, Respondents

claimed, led to “uncertainty in the minds of the

American public” about the causes of climate change.

J.A.111, ¶436.

But many of these activities that serve as the

predicate for Respondents’ tort theories took place at

a time when even the Environmental Protection

Agency recognized that “[t]he science of climate

change [wa]s extraordinarily complex[,] * * * still

evolving,” and plagued by “important uncertainties”

about “the factors that may affect future climate

change and how it should be addressed.”

Massachusetts v. EPA, 549 U.S. 497, 554 (2007)

(Scalia, J., dissenting) (quoting 68 Fed. Reg. 52930).

Indeed, Respondents claim that Petitioners have

known for decades—as early, perhaps, as the 1960s—

that “fossil fuel use would result in likely catastrophic

changes to the climate.” J.A.85, ¶329. But that cannot

be right. By 2001, even the EPA—no friend to fossil

fuels—still claimed that “a [causal] linkage between

the buildup of [GHGs] in the atmosphere and the

observed climate changes during the 20th century

cannot be unequivocally established.” Massachusetts

v. EPA, 549 U.S. at 553 (Scalia, J., dissenting) (quoting

Nat’l Rsch. Council, Climate Change Science: An

Analysis of Some Key Questions 17 (2001)).

2. Respondents’ claims thus necessarily ask the

courts to put their thumbs on the scale on one side of

an ongoing debate. Yet if history teaches anything, it

is that today’s consensus may be tomorrow’s

cautionary tale. As the many examples above show,

imposing massive financial liability on those who dare

to challenge the current orthodoxy would distort and

impoverish public discourse and make scientific

progress grind to a halt. Very few scientists will

challenge a prevailing view if doing so is actionable.

Moreover, the adverse consequences of a regime

that would allow the courts to impose such liability

extend beyond any single industry. For example, if

Respondents prevail here, pharmaceutical companies,

agricultural producers, and technology firms whose

public positions on issues involving emerging science

run contrary to prevailing understandings would all

be at risk—even if the prevailing understanding is

wrong.

And there is no reason such suits would be limited

to scientific contrarians: Those who challenge

economic, social, or other orthodoxies could also be

sued for the supposed downstream externalities of

their advocacy. Worse, allowing such suits could allow

competing and opposing tort suits by those on both

sides of controversial issues.

The result would be a marketplace of ideas in

which judges and juries decide what scientific or other

viewpoints could be safely voiced without existential

risk. This Court should not allow state tort law to

become a backdoor mechanism for enforcing scientific

orthodoxy at the expense of scientific advancement.

CONCLUSION

The First Amendment dangers of allowing

Respondents’ suit to proceed counsel strongly in favor

of a ruling for Petitioners. As Justice Alito has rightly

recognized, “[p]oliticians, journalists, academics, and

ordinary Americans discuss and debate various

aspects of climate change daily—its causes, extent,

urgency, consequences, and the appropriate policies

for addressing it.” National Rev., Inc. v. Mann, 589

U.S. 1088, 1093 (2019) (Alito, J., dissenting from the

denial of certiorari). Moreover, “[t]he core purpose of

the constitutional protection of freedom of expression

is to ensure that all opinions on such issues have a

chance to be heard and considered”—even if they come

from fossil fuel companies. Ibid. Because Respondents’

claims would effectively silence one side of the debate,

this Court should reverse the decision below.

Respectfully submitted,