The Supreme Court opened its term with a blockbuster fight over climate lawsuits that could decide whether state courts can hit energy companies for billions in damages.
Eight justices spent nearly two hours Monday on a gateway question that reaches far beyond Boulder County, Colorado: who gets to decide civil claims blaming energy firms for climate harms, and under which body of law. Justice Samuel Alito did not take part after recusing himself last week.
The case is Suncor Energy Inc. v. Commissioners of Boulder County, CO (25-170). It asks whether federal courts and the Clean Air Act control interstate air pollution claims, or whether states and localities can keep pressing for civil damages in their own courts. A decision is expected by next spring. The outcome will matter for a wave of similar suits across the country.
Fox News reported that local and state governments are seeking civil damages totaling billions of dollars to help pay for rebuilding after wildfires, rising sea levels, and severe storms they link to fossil fuel pollution. Energy companies and the Trump Justice Department say those claims belong in federal court and that the Clean Air Act limits what states and counties can do.
Boulder County sued in 2018. Colorado’s highest court allowed the case to move forward. Defendants include Canadian-based Suncor Energy, which operates the only major oil refinery in Colorado, and ExxonMobil, described as the largest oil company in the United States. Local officials also claim the firms misled the public.
Sarah Harris, a Justice Department lawyer, put the administration’s position in plain terms before the Court.
"Interstate air pollution is an inherently federal area. This suit egregiously exceeds constitutional limits on state authority."
That framing tracks the companies’ argument: greenhouse-gas policy is national in scope, and fragmented state-court actions would cut across the Clean Air Act’s design. Reuters reported the Court took up the ExxonMobil and Suncor appeal after the Colorado ruling, with nearly 60 similar lawsuits in play nationwide. Boulder seeks unspecified damages tied to infrastructure, environmental damage, emergency management, and public health costs.
An Exxon spokesperson said climate policy should not be set through fragmented state-court actions and that the company looked forward to making that case. Boulder Mayor Aaron Brockett countered that local communities are living with mounting costs and that the Court should affirm Colorado’s right to hold the companies accountable for harm in the state.
Chief Justice John Roberts pressed both sides and left open the possibility he could supply a decisive vote. With Alito out, a 4-4 split would leave the Colorado path intact for this lawsuit and allow it to proceed in state court. Readers tracking other high-stakes Supreme Court case interventions will recognize the same pattern: procedural posture can decide real-world leverage before any final merits ruling.
Roberts questioned why this dispute should be treated differently from other cross-border conduct that state courts already handle.
"There are a lot of familiar situations where conduct outside of the state has broad effects among other states, and yet we allow state courts in a particular state to bring litigation. I guess I'm not quite sure what makes this situation different from all those other ones, where we've allowed them to proceed in state court."
Justice Brett Kavanaugh spoke to the scale of the litigation strategy. He warned that a cascade of these suits could threaten not only the named energy firms but a much wider set of businesses.
"It is going to bankrupt, if there are enough of these [lawsuits], bankrupt these various defendants and certainly other defendants out there. Anyone is a potential defendant for a suit like this. Any manufacturer, any business."
He also tied the dispute to long-standing Court precedent and congressional reliance on it when Congress wrote and later amended the Clean Air Act.
"We don't have to reinvent the wheel because we've said this multiple times, and Congress, presumably, when doing [the Clean Air Act] and doing the Clean Air Act amendments, has relied on this Court's precedents establishing that this kind of pollution is a federal law matter unless Congress speaks otherwise."
That is the core conservative concern on display: localities using tort suits to impose national energy policy one jury and one county at a time, outside the statutes Congress actually enacted. The Trump administration’s backing of the companies fits a broader effort to keep major regulatory fights in federal channels rather than scatter them across friendly state courthouses, a theme also visible in recent Trump-related Supreme Court fights over executive authority.
Justice Alito recused last week and was absent Monday. Breitbart reported that he will not participate in the Suncor case, with arguments set for Oct. 5, and that he gave no public reason in the clerk’s letter stating he “will not continue to participate.” A coalition of 30 organizations had urged the Senate Judiciary Committee to examine his involvement over oil and gas holdings. The Court had previously said he had no financial interest requiring recusal; he withdrew anyway. The Court’s code of conduct says a justice should step aside when a reasonable person familiar with the circumstances might question impartiality.
The recusal leaves the bench at eight for this argument and raises the practical chance of a tie. A tie would not create national precedent but would let this Boulder suit continue on the path Colorado’s high court already cleared. Court-watchers following other justice-centered developments, including a recent Supreme Court justice bombshell, know personnel and participation questions can reshape a docket as much as any single opinion.
Justice Elena Kagan cast the climate cases as familiar public-harm litigation. She compared them to earlier state claims against tobacco and opioid companies brought on behalf of citizens and challenged the idea that air and water fall outside state reach.
"This is the same kind of lawsuit against the same kind of actors for the same kind of harm. Where does this principle come from, that states can't regulate in the air and water space?"
Justice Ketanji Brown Jackson asked oil companies’ lawyer Kannon Shanmugam why the Court should not wait. She noted the companies still have other federal issues pending in state court and asked why the justices should not hear all of those claims after state courts finish their federal considerations. The Court had specifically directed both sides to address whether it even has jurisdiction to hear the dispute at this stage, or whether the matter still belongs in state courts.
Some states accuse the current administration of rolling back mandated Clean Air Act protections and thereby abdicating regulatory authority. House Republicans, for their part, have described Boulder’s lawsuit against ExxonMobil and Suncor as an attack on American energy. The legal question before the justices is narrower and more structural: whether interstate air-pollution damages claims of this type may proceed under state law in state court, or whether federal law and federal courts control.
Monday’s argument is not an isolated local dispute. Dozens of lawsuits by states and municipalities are already filed. The Boulder case is the vehicle. If state courts can award climate damages against energy producers for global emissions, every manufacturer and business Kavanaugh flagged becomes a target in the most aggressive jurisdictions. If the Court holds that the Clean Air Act and federal constitutional limits bar that path, the litigation wave hits a wall and climate policy returns to Congress, federal agencies, and federal courts.
Suncor’s Colorado refinery footprint and ExxonMobil’s national scale make them convenient defendants. The design of the suits reaches further. Local governments want money for mitigation they attribute to fossil fuels. Companies and the Justice Department want a single federal framework instead of fifty state experiments. Taxpayers and ratepayers will live with whichever rule the court notes. Parallel docket fights over enforcement tools, including ICE detention rules under review, show the same institutional stakes: who sets national policy, and through which forum.
The justices left the courtroom with the jurisdiction question and the federal-versus-state allocation still unresolved. Briefs and argument put the Clean Air Act, constitutional limits on state authority, and the practical risk of serial local verdicts squarely in view. Spring will bring the answer.
When cities can sue national energy firms into submission over a global climate, Congress stops being the place where hard energy trade-offs get made, and voters lose the one forum built to make them.
