⚖ Oral Arguments, with Context

The Supreme Court hears Suncor Energy against the County Commissioners of Boulder County. Boulder's city and county governments sued Suncor and ExxonMobil in Colorado in twenty eighteen. They allege that the companies promoted and sold fossil fuels while misleading the public about climate risks, contributing to damage in Boulder. They seek money for climate-related property damage and costs of protecting their communities, including wildfire response and flood protection. Those are allegations, not findings that the companies caused those harms. After years of litigation over which court should hear the case, it returned to Colorado state court. The Colorado Supreme Court rejected the companies' argument that federal law barred these claims and allowed them to proceed. The companies now seek reversal, arguing that federal law, including the Clean Air Act, leaves no room for these state-law climate claims. Boulder says it seeks compensation for the companies' production and deception, not a court order limiting emissions. The underlying damages case is unfinished, and the Court must also decide whether it has jurisdiction to review this dispute now. Much of the debate concerns federal common law: specialized rules developed by federal judges rather than enacted by Congress. Displacement means a federal statute replaces those judge-made rules; preemption concerns federal law overriding state law. Replacing federal common law does not by itself answer whether these state-law claims survive. Kannon Shanmugam, of Davis Polk and Wardwell, represents the companies and will argue that Boulder's claims are barred.

Suncor Energy (U.S.A.) Inc. v. Commissioners of Boulder County (No. 25-170) — Supreme Court of the United States, argued October 5, 2026.