On Monday, the Supreme Court’s conservative majority opens its term with the biggest climate case in years. The right has a real affordability argument for the oil companies and a real textualist argument against them. The justices have to pick.
By Michael Phillips | Riptide
At 10 a.m. Eastern on Monday, the Supreme Court will hear the first case of its new term, Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County. Eight justices will hear it. On September 28, the Court’s clerk told the parties that Samuel Alito would not continue to participate, without giving a reason. His disclosures show stock in other oil companies, including ConocoPhillips and Phillips 66, but not in Exxon or Suncor.
The case is one of dozens of similar suits in which state and local governments accuse fossil fuel companies of contributing to climate change and deceiving the public about it, and billions of dollars could ride on the outcome. More than 40 states and roughly 200 members of Congress have filed briefs on one side or the other. The question for the Court is narrower than that and bigger than it looks: whether federal law keeps a Colorado county from using state tort law to make oil companies pay for climate harms at all.
For conservatives, it is an awkward case, because the movement’s instincts point in two directions at once.
“For conservatives it is an awkward case, because the movement’s instincts point in two directions at once.”
What the Court is actually deciding
Boulder County and the City of Boulder sued Suncor and ExxonMobil in April 2018. They originally pleaded six Colorado-law claims: public nuisance, private nuisance, trespass, unjust enrichment, a violation of the Colorado Consumer Protection Act, and civil conspiracy. The trial court dismissed the consumer-protection count without prejudice in June 2024, so five common-law claims remain. Boulder seeks money damages for the costs of climate effects, not an order limiting emissions or halting fossil fuel sales. That distinction is central to its argument that the suit compensates local injuries rather than regulating national climate policy. The companies argue that federal law bars every remaining claim. The Colorado Supreme Court disagreed 5–2 in May 2025, and the U.S. Supreme Court took the case in February.
There are two questions. The first is whether federal law precludes state-law claims seeking relief for injuries allegedly caused by interstate and international greenhouse-gas emissions. The companies offer three routes to yes: the Constitution’s structure, which they say stops one state from regulating conduct in others; the federal government’s foreign-affairs power; and the Clean Air Act. Boulder answers that the Act displaced the old federal common law of interstate pollution but did not preempt ordinary state remedies, and that its claims sit within traditional state authority.
The second question is whether the Court can hear the case at all. The Colorado decision sent the case back for further proceedings. Boulder says that is not a final judgment, and the justices told both sides to brief the point. The companies counter that the ruling stripped them of a federal defense and settled a self-contained proceeding.
The Trump administration is backing the companies. The Solicitor General is recused, so a deputy will take 10 minutes of argument, on top of 20 for the companies and 30 for Boulder.
One distinction matters more than the headlines suggest. Boulder’s complaint rests on two theories. The “production” theory says the companies are liable for selling fossil fuels while knowing the climate consequences. The “deception” theory says they ran a decades-long campaign to mislead the public. Michael Burger, a climate-law scholar who also represents governments in other climate cases, argues that claims built on deception enforce a duty not to mislead, which is different from regulating emissions, and that they survive even if the production claims do not. The justices of Maryland’s Supreme Court, as we will see, have already split on that line.
The case the right makes for the companies
Regulation by another name. The companies and the federal government argue that holding fossil fuel companies liable for a global atmospheric problem is climate policy set by a county judge and jury. Alabama, West Virginia and 24 other states told the Court that local governments like Boulder would end up imposing policy on citizens of other states who cannot vote them out. The companies add that the Clean Air Act already gives the EPA the job of setting national air standards, and that Boulder’s theory would invite fifty states and countless localities to apply conflicting rules to the same global conduct.
The price tag. Industry-aligned amici argue that liability on this scale would lead companies to cut back production, raise energy prices and pass costs to consumers. The Buckeye Institute calls the suit a de facto carbon tax. Boulder’s allies, including a group of climate economists, say tort liability would simply make producers account for costs they now impose on others, with little harm to growth. Both sides are projecting. The affordability question, though, is not an abstraction in a week when the Senate was unable to agree on who pays for the grid. At least some costs imposed on producers can ultimately reach consumers, depending on market conditions and how companies respond.
Maryland’s example. On March 24, the Maryland Supreme Court became the first state high court to affirm a complete dismissal of a municipal climate suit, in cases brought by Baltimore, Annapolis and Anne Arundel County. Writing for the majority, Justice Brynja Booth held that the claims were displaced by federal common law and preempted by the Clean Air Act, and, in the alternative, that they failed under Maryland tort law. Chief Justice Matthew Fader agreed on preemption but would have stopped there. Lawyers at Jones Day note that the state-law holding ends those cases whatever the U.S. Supreme Court says.
The court was not unanimous, and its split previews Monday’s. Justice Peter Killough dissented, writing that the majority had decided the case the defendants described rather than the one the plaintiffs brought, because the localities were not challenging a permit, seeking emission cuts or asking the court to set a standard. Justice Shirley Watts joined him in part, and would have let the fraud and deceptive-marketing claims of Baltimore and Annapolis go forward. That is the production-versus-deception line again.
Maryland is also not the only state high court to have spoken. Hawaii’s Supreme Court allowed Honolulu’s suit to proceed in October 2023, and the U.S. Supreme Court declined to review that interlocutory decision in January 2025, with no justice noting support for taking it. Colorado took a similar view of preemption in May 2025. On the central preemption question, the Maryland ruling conflicts directly with both, and the split is broader than Maryland against Colorado. Chevron attorney Theodore Boutrous points to dismissals in Delaware, New Jersey, New York, Pennsylvania, Puerto Rico and South Carolina as a “growing chorus” on the other side.
The case for Boulder
Boulder’s defenders say the suit seeks damages, not an emissions standard. It asks whether companies that allegedly misled the public must pay for local harms, and state law policing deceptive conduct is among the most conventional uses of state police power. They note that the Clean Air Act has no express preemption of tort suits, that its saving clauses preserve state remedies, and that a company can comply with every emissions rule and still be truthful. Nineteen states, D.C., 13 federally recognized tribes, and New York City are among the amici arguing that states and localities must be able to recover costs from the parties they allege caused them, and that a ruling for the companies would reach well beyond climate. They would add that the ability to sue is not the same as winning: Boulder still has to prove causation and damages.
The right’s problem
The conservative case for the companies, which Boulder’s defenders dispute on the law, also runs into the conservative theory of how preemption works.
On April 22, in Hencely v. Fluor Corp., the Court rejected the Fourth Circuit’s categorical “battlefield preemption” rule, which held that state tort claims arising from a contractor’s wartime conduct were barred. Justice Clarence Thomas wrote for a 6–3 majority that included Gorsuch, Barrett and the three liberals; Alito, Roberts and Kavanaugh dissented. The Fourth Circuit’s rule, Thomas wrote, “lacks any foundation in the Constitution, federal statutes, or our precedents.” Thomas, quoting earlier opinions, put the principle this way: there is no federal preemption in vacuo, without a constitutional text or a federal statute behind it. In a 2019 plurality opinion in Virginia Uranium v. Warren, joined by Thomas and Kavanaugh, Gorsuch wrote that judges should not preempt state law on the strength of some “brooding federal interest.”
“If conservatives would be uneasy with a rule that immunized a different industry in a different case, they should want a limiting principle here.”
The analogy to Suncor is not exact. Hencely involved no Clean Air Act, no interstate pollution and no foreign-affairs claim. But the companies’ constitutional argument is that a category of dispute, interstate emissions, is federal by its nature, whatever the statute says. That is the kind of rule the Hencely majority declined to adopt. The companies also lean on principles that bar one state from regulating another, and Boulder’s allies note that in National Pork Producers Council v. Ross (2023), all nine justices rejected an “almost per se” rule against state laws with extraterritorial effects. That case arose under the dormant Commerce Clause, and the Court acknowledged that other constitutional provisions may limit extraterritorial regulation, which is where the companies’ structural argument lives.
Jonathan Adler, a William & Mary law professor who writes at the Volokh Conspiracy, filed a brief arguing that no statute or precedent supports wholly preempting these cases. He is careful about it: that does not mean the claims should succeed, nor that no other grounds could narrow them, but those grounds are not in the question before the Court. He also observes that people skeptical of climate policy or worried about energy prices tend to line up behind the companies, which can obscure the legal question. By his count, 40 top-side briefs back the companies and 28 back Boulder.
Then there is the federal government’s own position. In March 2023, the Biden administration’s Solicitor General urged the Court to deny an earlier, removal-stage petition in this same litigation, and the Court did. The Trump administration has reversed course. An April 2025 executive order, “Protecting American Energy from State Overreach,” told the Attorney General to act against state climate tort suits, and the Justice Department sued Hawaii and Michigan to stop theirs. A federal court dismissed the Michigan case in February. A change of position after a change of administration is not a scandal. But a movement that has spent decades arguing that federal power needs a source in the text should be able to say where the text is.
“A movement that has spent decades arguing that federal power needs a source in the text should be able to say where the text is.”
Run the swapped-jerseys test. Colorado’s brief, joined by California, seventeen other states and D.C., warns that a structure-only preemption rule would reach far beyond climate. State tort law has long been the tool for border-crossing harms from asbestos, lead paint, tobacco and opioids. If conservatives would be uneasy with a rule that immunized a different industry in a different case, they should want a limiting principle here. Boulder and its allies say the companies’ theory has none, and the justices will want an answer.
Cost causation cuts both ways
“The strongest reply from the right is about causation and scale.”
In the data-center fight, the conservative principle was simple: the party that creates a cost pays for it. Boulder makes the same argument, that taxpayers who now pay for wildfire defense, drought and flood repairs should be able to shift those costs to the producers they say caused them. The strongest reply from the right is about causation and scale. A data center is an identifiable load on an identifiable grid, with a meter. Global emissions are produced by billions of people and the consumers who burn the fuel, and the companies argue that no one defendant’s conduct can be traced cleanly to Boulder’s bridges. That is an argument the companies can make on the merits, in a trial court, if the case continues, which is a different thing from saying the claim may not be brought.
“A data center is an identifiable load on an identifiable grid, with a meter. Global emissions are produced by billions of people.”
How it could come out
Several outcomes are live. The Court could side broadly with the companies and end most of these suits. It could side with Boulder and send the case back toward discovery and trial. It could split the claims, barring production theories and leaving deception theories standing. Or it could hold that it lacks jurisdiction, leaving the Colorado ruling in place without a national rule.
The arithmetic is unusual. With Alito out, five votes carry the day, and a 4–4 split would leave the Colorado judgment in place without setting a precedent, so the conflict with Maryland would remain. In Hencely, six justices (Thomas, Gorsuch, Barrett, and the three liberals) rejected categorical preemption, and the three dissenters included Alito. If those six reached the merits and held together here, the vote against the companies’ preemption theory would be 6–2. Two defections would produce a tie, and three would give the companies the five votes they need. All of that assumes the Court reaches the merits at all. That is a scenario, not a prediction. Past alignments are an imperfect guide: in Virginia Uranium in 2019, Kavanaugh joined Gorsuch’s anti-preemption plurality, while Roberts and Alito dissented. Kavanaugh then dissented in Hencely. Hencely never touched the Clean Air Act or the foreign-affairs theory, and this case turns on both.
What to listen for on Monday
- Whether the justices treat this as an emissions case or a deception case. The answer could determine whether the companies’ preemption theory reaches Boulder’s deception theory.
- Whether Thomas, Gorsuch, or Barrett press the federal government to name the textual source of constitutional-structure preemption.
- How much time goes to jurisdiction. If the questions focus on finality, the Court may be looking for an exit.
- Whether anyone asks for a limiting principle: what stops the rule from reaching asbestos, tobacco or opioid suits.
- Whether the justices distinguish damages from regulation. Boulder says a judgment compensating local costs is different from an emissions standard. The companies say damages imposed because of global emissions necessarily regulate the conduct that produced them.
- The deputy Solicitor General’s ten minutes, particularly how the United States explains its 2023 position.
Sources: Supreme Court docket No. 25-170 and the Court’s argument calendar; Legal Information Institute, Supreme Court Bulletin preview of Suncor v. Boulder County (questions presented, parties’ arguments, amici); Reuters (Sept. 28, 2026) and Associated Press (Sept. 28, 2026) on Justice Alito’s recusal; Motion of the United States for leave to participate in oral argument (July 28, 2026) and the Brief for the United States as amicus curiae (Sept. 2025); Congressional Research Service, “State-Law Climate Tort Suits and Suncor Energy v. Boulder County: A Primer for Congress” (2026); Hencely v. Fluor Corp., No. 24-924 (Apr. 22, 2026), and Bloomberg Law’s report on it; CNN (Oct. 3, 2026) on Justices Thomas and Gorsuch and preemption; Just Security, Michael Burger (Sept. 29, 2026), who discloses that he represents governments in other climate cases; Jonathan H. Adler, The Volokh Conspiracy (Aug. 6, 2026); Maryland Matters (Mar. 25, 2026) and law-firm summaries, including Jones Day’s, of the Maryland Supreme Court’s March 24, 2026 decision; Harvard Environmental & Energy Law Program, “Suncor Energy v. Boulder County: The United States Urges the Supreme Court to Stop”; Climate Litigation Database docket entries, including the 2023 Solicitor General brief and the list of amici; Legal Planet’s guide to the case.
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