Supreme Court hears Boulder climate suit with Alito recused

The US Supreme Court opened its October 2026 term on Monday with nearly two hours of argument in Suncor Energy Inc. v. County Commissioners of Boulder County, docket 25-170. The city and county of Boulder want to keep a state-court suit alive against Suncor and ExxonMobil for the local cost of climate change. The companies want the court to say federal law blocks that suit. Justice Samuel Alito is recused. With eight justices sitting, a 4-4 tie leaves the Colorado Supreme Court ruling in place, and that ruling let Boulder go forward.

Boulder filed in Colorado state court about eight years ago. Suncor, part of the Canadian energy group, runs the only two oil refineries in Colorado. ExxonMobil is the largest US energy company. Boulder says both deceived the public about the effect of fossil fuels and that their production, refining and marketing contributed to harms the county now pays to manage, including protection of public property and residents' property. The suit is a tort claim for money. It is not a demand for a permit, a rule, or an injunction against drilling.

The two questions the court actually granted

The justices agreed to hear two questions. The first is whether federal law precludes state-law claims for injuries said to be caused by the effect of interstate and international greenhouse-gas emissions on the global climate. The second is whether the court has statutory and Article III jurisdiction to hear the case at all. The second question is unusual in a merits grant. The companies appealed a pretrial ruling, not a final judgment. Boulder argues that a defendant's added risk of future liability, at the pleading stage, is too speculative an injury to support appellate standing.

The Colorado Supreme Court, in a decision reported at 586 P.3d 161 and numbered 2025 CO 21, affirmed the denial of the companies' motion to dismiss on federal-preemption grounds. The US Supreme Court then granted review of that preemption holding and added the jurisdiction question. Oral argument was 5 October 2026. Amy Howe of SCOTUSblog wrote that, after the argument, it was not clear a majority agreed with the companies. She noted Alito's recusal as the fact that makes a tie meaningful.

Why a tie is a result

An evenly divided court affirms the judgment below without an opinion that binds other courts. If the split is 4-4, Boulder keeps the Colorado ruling and returns to state court for the rest of the case: discovery, a possible trial, a possible damages number. That outcome would not decide the preemption question for Honolulu, or for the other cities and states that have filed similar suits. It would decide it for Boulder, for now, and it would leave the national question open until a full bench hears a later case.

The companies' preemption argument is that climate harm from global emissions is the kind of interstate and international dispute the Constitution and the Clean Air Act leave to federal law, not to a Colorado jury. Boulder's answer is that fraud and the local cost of a product are ordinary state torts, and that Congress has not displaced them. Both sides have made those points in other courts for years. Monday's hearing added a procedural trap. If the justices decide they lack jurisdiction, they dismiss without reaching preemption, and the Colorado ruling also stands, by a different route.

Alito's recusal was noted by SCOTUSblog and was not explained in the public argument summary. Recusals at the court often track stock ownership. The practical effect does not depend on the reason. Eight votes, a live standing fight, and a state-court case that has already survived a motion to dismiss are the facts that will decide whether Boulder ever puts a refinery manager on the stand.