Supreme Court Weighs Climate Lawsuits Against Oil Companies

The Supreme Court on Monday, Oct. 5, 2026, heard nearly two hours of argument in Suncor Energy Inc. v. County Commissioners of Boulder County. Boulder sued Suncor Energy and ExxonMobil eight years ago under state law for climate-related costs. Justice Samuel Alito recused over oil and gas stock, leaving eight justices. A 4-4 tie would leave the Colorado Supreme Court ruling intact, allowing the suit to proceed. That court held Boulder's claims were not preempted by federal law. Kannon Shanmugam, for the companies, called the suit an "unprecedented effort to use state law to regulate global conduct" and argued federal law governs interstate pollution. The Trump administration supported the companies. Kevin Russell, for Boulder, said states may remedy in-state injuries from out-of-state conduct. Chief Justice John Roberts asked "what makes this situation different from those" and said "That's a question of relief." Justice Elena Kagan said the "suit appears to be based on the old 1990s tobacco suits." Justice Brett Kavanaugh said precedents "make crystal-clear that interstate air and water pollution are matters for federal law." Justice Ketanji Brown Jackson called review "premature." Shanmugam cited roughly 60 similar suits. The Court added a question on its jurisdiction. The outcome could determine whether those cases proceed nationwide.