SUPREME COURT DROPS UNANIMOUS 9–0 BOMBSHELL — WASHINGTON ERUPTS

The Supreme Court is preparing to hear one of the most consequential climate-liability disputes to reach the justices in years.

But before the Court decides whether Colorado communities can use state tort law to pursue fossil-fuel companies over alleged climate harms, the justices may have to answer a more basic question.

Do they have jurisdiction to decide the case at all?

The Court has scheduled Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County for oral argument on October 5, the opening day of the Supreme Court’s October 2026 term. It will be the first case argued that morning.

The stakes extend well beyond Colorado.

Boulder County and the City of Boulder are seeking damages from Suncor and ExxonMobil under Colorado common law for costs they attribute to climate change.

The energy companies argue that claims built around the effects of greenhouse-gas emissions from across the United States and the world cannot be governed by the law of one state.

Boulder argues that it is doing something much more ordinary.

It says Colorado law should be allowed to compensate Colorado communities for injuries allegedly caused by wrongful commercial conduct that produced harm inside Colorado.

That is the central divide.

But it is not the only question before the Supreme Court.

When the justices granted review on February 23, they accepted the companies’ question asking:

Whether federal law precludes state-law claims seeking relief for injuries allegedly caused by the effects of interstate and international greenhouse-gas emissions on the global climate.

Then the Court added a question of its own.

The parties must also brief and argue whether the Supreme Court possesses statutory and Article III jurisdiction to hear the case.

That addition could become enormously important.

It means this case is not simply a referendum on climate lawsuits.

The justices first may have to determine whether this particular dispute arrived at the Supreme Court through a procedural route that federal law permits them to review.

If the answer is no, the Court could potentially dispose of the case without deciding the broad climate-preemption question at all.

The underlying litigation began years ago.

Boulder County and the City of Boulder sued ExxonMobil and Suncor entities in Colorado state court, asserting claims for public nuisance, private nuisance, trespass, unjust enrichment and civil conspiracy.

They allege that the companies produced, promoted, refined, marketed and sold fossil fuels while knowing that widespread use of those products would contribute to climate change.

Boulder also alleges that the companies concealed or misrepresented information about those climate effects.

Those allegations remain allegations.

The Colorado Supreme Court did not decide that Exxon or Suncor deceived the public.

It did not determine that the companies caused a legally compensable portion of Boulder’s climate damage.

It did not award damages.

And it did not decide how causation could ultimately be proved in a system as complex as the global climate.

The court explicitly said it was expressing no opinion on the ultimate viability of Boulder’s claims.

That distinction matters.

The case presently before the U.S. Supreme Court is principally about whether Boulder is legally allowed to attempt to prove those claims under Colorado law.

It is not yet about whether Boulder has actually proved them.

The remedies sought also require more precision than some descriptions suggest.

Boulder is not asking the court to impose a Colorado emissions limit on oil producers worldwide.

It says it is seeking monetary compensation for costs associated with responding to climate impacts.

According to the Colorado Supreme Court’s description of the complaint, those costs include wildfire response and mitigation, flood-control and drainage work, drought management and repairs to physical damage to public buildings.

Boulder specifically says it is not asking the court to enjoin oil and gas operations or sales in Colorado or anywhere else.

It also says it is not seeking judicially imposed emissions controls.

That is central to Boulder’s legal theory.

The communities characterize the lawsuit as a traditional state tort action seeking money for local injuries.

Suncor and Exxon characterize the same lawsuit very differently.

From their perspective, the form of the remedy does not solve the federalism problem.

If liability depends on the theory that worldwide production and consumption of fossil fuels generated greenhouse gases that collectively changed the global climate, the companies argue that Colorado is effectively imposing its law on activity occurring far beyond Colorado.

The fact that Boulder asks for money rather than an injunction does not necessarily make that effect disappear.

That disagreement produced a divided decision from the Colorado Supreme Court in May 2025.

The majority concluded that federal law did not preempt Boulder’s claims and allowed the litigation to continue.

Five justices joined the majority.

Two dissented.

The majority began with a major Supreme Court precedent:

American Electric Power Co. v. Connecticut.

In that 2011 case, the U.S. Supreme Court held that the Clean Air Act displaced the federal common-law right plaintiffs had invoked to seek abatement of carbon-dioxide emissions from fossil-fuel-fired power plants.

But AEP did not resolve the precise question now presented in the Boulder litigation.

The Court said that after federal common law was displaced, the availability of a state lawsuit would depend in part on the preemptive effect of the Clean Air Act.

The justices did not decide that issue because it had not been sufficiently briefed in that case.

That unresolved sentence is now helping drive a Supreme Court case fifteen years later.

Colorado’s majority reads AEP to mean that once federal common law has been displaced, courts should look directly at the Clean Air Act and apply ordinary principles of statutory preemption.

Under that approach, Boulder wins at this stage.

The Colorado Supreme Court found no express provision of the Clean Air Act categorically preempting state common-law tort claims.

It also rejected the argument that Congress completely occupied the entire field of air-pollution regulation.

The majority noted that the Clean Air Act itself preserves significant roles for states and contains savings provisions protecting some state authority and common-law remedies.

The majority also rejected conflict preemption.

It said the companies had not shown that complying with both the Clean Air Act and Colorado tort law was impossible.

Nor, in the majority’s view, had they demonstrated that Boulder’s damages claims frustrated the objectives of federal air-pollution law.

That is why describing the companies’ argument simply as “the Clean Air Act occupies the field” is incomplete.

Field preemption is part of the dispute.

But the energy companies’ broader case reaches beyond conventional statutory field preemption.

They argue that the constitutional structure of the United States has long prevented one state from imposing its own law on interstate pollution controversies that demand a uniform federal rule.

Their certiorari petition frames the question accordingly:

Federal law, they contend, must control claims involving the effects of interstate and international greenhouse-gas emissions because no single state can constitutionally govern conduct occurring throughout the nation and abroad.

The Colorado Supreme Court majority rejected that characterization.

It drew a line between classic interstate-pollution cases and Boulder’s current lawsuit.

Traditional federal common-law pollution cases, the majority reasoned, generally involved one sovereign attempting to stop pollution physically emanating from another state.

Boulder, by contrast, is suing upstream producers for money damages associated with production, promotion, sale and marketing of fossil fuels.

That distinction, in the majority’s view, makes ordinary state tort law much more relevant.

The majority also rejected the proposition that a damages award automatically becomes regulation merely because it may change a defendant’s future behavior.

That principle could have consequences far beyond climate litigation.

Tort damages routinely encourage companies to alter behavior.

Product-liability awards can influence product design.

Negligence judgments can change safety practices.

Fraud judgments can change marketing.

If every monetary judgment with behavioral effects were classified as regulation, a very large portion of state tort law could potentially become vulnerable to federal preemption arguments.

The Colorado court refused to take that step.

The dissent saw the case almost exactly the opposite way.

Justice Carlos Samour Jr., joined by Justice Brian Boatright, argued that interstate and international air pollution has historically required federal rather than state rules precisely because pollution ignores political borders.

In his view, the majority had allowed Boulder to do through tort damages what Colorado could not constitutionally do through direct regulation.

The dissent emphasized that the causal chain underlying Boulder’s lawsuit necessarily runs through worldwide greenhouse-gas emissions.

Oil is produced.

Fossil fuels are sold.

Consumers and businesses burn them across numerous jurisdictions.

Greenhouse gases mix in the atmosphere.

The global climate changes.

Boulder then attributes a portion of its local physical and financial injuries to that global process.

For the dissent, that made the lawsuit inherently interstate and international regardless of how the complaint labeled its causes of action.

The dissent also challenged the majority’s distinction between regulation and damages.

A sufficiently large damages judgment can change corporate behavior just as effectively as a regulation, Justice Samour reasoned.

If every state or municipality can impose liability based on its own tort rules for the same worldwide emissions, the result could become a patchwork of overlapping and potentially inconsistent state standards.

That concern lies at the heart of Suncor and Exxon’s Supreme Court case.

Suppose Colorado imposes substantial liability because a company produced and marketed fossil fuels.

Another state might apply a different liability standard.

A third might reject liability entirely.

A fourth could demand a different level of disclosure.

Dozens of local governments could potentially pursue their own claims based on different state-law theories.

The energy companies argue that the practical result would be decentralized regulation of conduct that necessarily occurs across state and national borders. That is the theory they are asking the Supreme Court to accept.

But describing that consequence as already established would go too far.

The Colorado majority rejected the premise that Boulder is regulating global emissions at all.

It characterized the claims as compensation for allegedly tortious conduct and local injury—not an attempt to establish emissions standards for the rest of the country.

That is one of the fundamental questions the Supreme Court now confronts.

When does a state damages action become regulation in substance?

There is no simple rule that every damages award is purely compensatory.

There is also no simple rule that every damages award affecting future behavior is regulatory.

The justices may have to decide where this type of climate litigation falls between those poles.

The foreign-affairs dimension makes the dispute even more difficult.

Greenhouse gases do not stop at the Canadian border, the Mexican border or any other national boundary.

Boulder’s theory concerns climate effects allegedly resulting from fossil-fuel production and use worldwide.

The companies therefore argue that allowing Colorado law to impose liability based on international emissions risks intruding into an area constitutionally entrusted to the federal government.

The Colorado majority rejected that argument too.

It concluded that Boulder was not attempting to create foreign policy and that the defendants had not identified a specific federal foreign-policy rule with which the Colorado tort claims conflicted.

In the majority’s view, interaction between state tort law and multinational companies does not automatically transform a local damages action into unconstitutional foreign policymaking.

The dissent again disagreed.

It warned that imposing state-law liability for activity occurring outside the United States could affect international energy markets and interfere with federal management of foreign relations.

That disagreement gives the Supreme Court another possible path to a broad decision.

A ruling for the companies need not necessarily depend solely on the text of the Clean Air Act.

The Court could potentially ground its decision in broader constitutional principles limiting one state’s authority over conduct occurring elsewhere.

But that is a contested theory, not an established outcome.

And the Supreme Court’s own additional jurisdiction question could stop the justices before they ever reach it.

That procedural issue arises because of the unusual way the Colorado Supreme Court heard the dispute.

The case had not proceeded through an ordinary final trial and final appellate judgment.

Instead, the energy companies invoked Colorado Appellate Rule 21 and asked the Colorado Supreme Court to exercise what Colorado calls its original jurisdiction.

The state supreme court agreed to consider the preemption question, rejected the companies’ arguments and sent the case back to the trial court for further proceedings.

That creates a potential problem under federal law.

28 U.S.C. §1257 generally authorizes the U.S. Supreme Court to review final judgments or decrees from the highest court of a state.

Boulder’s lawsuit is plainly not finished.

There has been no trial.

There has been no final damages award.

The Colorado court expressly returned the case to the trial court.

So the Supreme Court has asked the parties to address why this ruling qualifies for federal review now.

Suncor and Exxon argue that the Court does have jurisdiction.

They contend that the Colorado proceeding was sufficiently final as to the federal preemption question and that forcing them to continue years of litigation after their federal defense has been conclusively rejected creates a concrete injury the Supreme Court can remedy.

Boulder disputes that.

Its position is essentially that the companies are trying to obtain Supreme Court review of an interlocutory decision in litigation that remains unfinished.

That disagreement could have major consequences.

If the justices conclude §1257 does not permit review at this stage—or that Article III presents an independent obstacle—the writ could potentially be dismissed without resolving whether Boulder’s climate claims are preempted.

The lawsuit would then continue in Colorado state court.

The companies could potentially return to the Supreme Court later after a sufficiently final judgment.

That possibility makes the October 5 argument more complicated than a simple conservative-versus-progressive showdown over climate policy.

The first portion of questioning may focus heavily on federal jurisdiction.

And jurisdiction is not a technicality the Court can simply ignore because the merits question is important.

Federal courts possess only the jurisdiction supplied by the Constitution and Congress.

The Supreme Court itself highlighted the issue when it granted the case.

If the Court reaches the merits, however, the implications could be national.

Climate-related state tort litigation has proliferated in multiple jurisdictions.

A broad ruling that federal law categorically precludes claims based on interstate and international greenhouse-gas emissions could make it significantly harder for cities, counties and states to pursue fossil-fuel companies through ordinary state tort theories.

The precise effect would depend on how broadly the Court writes its opinion.

A narrow ruling could target only claims whose causal theory depends on worldwide emissions.

A broader one could affect climate lawsuits framed around production, promotion, marketing or alleged deception as well.

That distinction will matter.

Boulder’s complaint is not limited to the assertion that fossil fuels emit greenhouse gases.

It also alleges that the companies knew about climate risks and misrepresented or concealed them while continuing to promote fossil-fuel use.

That creates a possible dividing line between two kinds of claims.

One theory says:

You produced fossil fuels, people burned them worldwide, emissions altered the climate and therefore you owe us money.

Another says:

You possessed material information about the risks of your products and deceptively marketed those products in violation of ordinary state-law duties.

Those theories overlap in Boulder’s case, but they are not analytically identical.

The Supreme Court may have to decide whether federal preemption turns on the form of the claim, its factual basis or the ultimate injury for which compensation is sought.

The energy companies want the Court to look through the tort labels to the underlying causal mechanism.

Whatever the name of the claim, they argue, Boulder cannot reach its alleged injuries without relying on worldwide greenhouse-gas emissions.

Therefore the case necessarily implicates federal control over interstate and international pollution.

Boulder wants the Court to focus on the conduct and remedy.

It is alleging wrongful commercial conduct.

It is seeking compensation for Colorado injuries.

It is not asking a Colorado judge to set emissions standards for Texas, Saudi Arabia, Canada or anywhere else.

From that perspective, the companies’ theory would dramatically expand federal preemption into traditional areas of state tort law.

Neither position can simply be dismissed as wordplay.

Large tort awards can influence national markets.

State law has long imposed liability for conduct occurring partly outside a state when the resulting injury occurs inside it.

The constitutional question is where ordinary state authority ends when the relevant causal mechanism is a global atmospheric phenomenon.

That is the difficult line the Court may have agreed to draw.

It is also why claims that the case straightforwardly involves “activist local governments regulating the national economy” are political characterizations rather than established legal facts.

The dissent in Colorado shared much of that concern.

The majority rejected it.

The U.S. Supreme Court has granted review precisely because the issue remains contested.

Likewise, claims that Boulder is merely asking polluters to pay an ordinary local damages bill under settled state tort law state only the plaintiffs’ side.

Climate causation differs from a conventional nuisance dispute involving smoke from a factory next door or contamination flowing across one property line.

The alleged emissions originate from innumerable uses of fossil fuels across the world.

The resulting greenhouse gases mix globally.

And the alleged injuries emerge through complex climatic processes.

Those characteristics give the defendants a serious federalism argument even though Boulder requests compensation rather than direct emissions controls.

The proper legal consequence of those facts is exactly what the Supreme Court will consider.

The consumer-price argument also requires caution.

Critics of the lawsuits say repeated multibillion-dollar liabilities could increase the cost of energy, discourage investment or cause companies to change production and marketing practices nationwide.

Those are plausible economic concerns.

But the Supreme Court is not being asked to decide whether gasoline would rise by a particular number of cents or whether a particular amount of investment would disappear.

Those outcomes would depend on the size and number of judgments, how costs were absorbed or passed through, market competition and numerous other factors.

They should be treated as predicted consequences of liability—not as facts already established by the Colorado case.

The same applies to the opposite argument that successful lawsuits would necessarily produce a particular amount of climate adaptation or emissions reduction.

No damages judgment has been entered.

The case has not even reached trial.

The current dispute is about whether Colorado law can remain in the courtroom long enough for Boulder to try to prove its case.

Another important point is what the Colorado Supreme Court did not hold.

It did not conclude that states have unlimited power to regulate out-of-state emissions.

It did not authorize Colorado to impose its own emissions standards on another state.

It did not say foreign affairs are a matter of state authority.

It concluded only that these particular tort claims, as currently framed, were not preempted by federal law.

Likewise, Suncor does not need to prove that Congress enacted an explicit clause saying “Boulder may not sue.”

Its argument is that the Constitution, the history of federal control over interstate pollution and the Clean Air Act together establish that a controversy depending on global emissions cannot be governed by the tort law of a single state.

That difference explains why precedent such as AEP has become so important.

Both sides rely on the same Supreme Court decisions.

They disagree about what follows from them.

Colorado’s majority says:

Federal common law has been displaced, so look to ordinary statutory preemption under the Clean Air Act.

The dissent and energy companies say:

The historical reason federal law governed interstate pollution does not vanish merely because Congress replaced judge-made federal law with a statute.

That is a genuine doctrinal disagreement.

The Supreme Court now has an opportunity to settle it nationally.

Or it may decide this is not yet the case in which it can do so.

That is why the jurisdiction question may prove as important as climate policy itself.

If the Court finds jurisdiction and rules broadly for Suncor and Exxon, the decision could establish a major federal barrier to state and local climate-damages litigation.

If it finds jurisdiction and sides with Boulder, state-law climate cases could gain significant momentum, although individual plaintiffs would still have to prove causation, liability and damages under their respective state laws.

A Boulder victory on preemption would not mean automatic victory at trial.

The Colorado Supreme Court has already made that clear.

And if the Supreme Court dismisses for lack of jurisdiction, neither side would necessarily receive the definitive national answer it wants.

Colorado litigation could continue while the broader legal conflict remains unresolved.

So October 5 will not simply ask whether the Supreme Court supports or opposes climate litigation.

The questions are more precise.

Can the Supreme Court review this Colorado ruling now?

If it can, does federal law leave Colorado room to use ordinary tort law to compensate local climate injuries?

Or does the interstate and international nature of greenhouse-gas emissions require a uniform federal rule that prevents one state from imposing liability?

And does a request for damages remain a local tort remedy when liability is calculated through the effects of worldwide fossil-fuel use?

Those are federalism questions as much as climate questions.

The conservative concern is real: allowing many states and municipalities to impose different liability rules on conduct tied to a single global emissions system could have national economic and regulatory consequences.

Boulder’s counterargument is real too: a rule barring state tort claims merely because wrongful conduct has effects beyond one state could remove traditional remedies for local injuries without Congress ever expressly saying so.

The Supreme Court now has both positions directly before it.

What it has not done is decide which one is correct.

The Colorado Supreme Court allowed Boulder’s lawsuit to continue.

The U.S. Supreme Court agreed to review that decision.

Oral argument is officially scheduled for October 5.

A ruling would ordinarily be expected sometime during the Court’s 2026–27 term, potentially by late June 2027, although the Court is not legally required to issue the decision on a particular date.

For now, the most consequential fact is not that Boulder has won its climate case.

It has not.

Nor have Suncor and Exxon defeated it.

They have not.