Supreme Court opens term with Exxon and Suncor bid to end Boulder climate lawsuit

The U.S. Supreme Court opens its new term on Monday, October 5, with oral argument in Suncor Energy v. County Commissioners of Boulder County, No. 25-170, a bid by Exxon Mobil (XOM) and Suncor Energy (SU) to end a Colorado climate lawsuit. It is the first case argued in the 2026-27 term, according to SCOTUSblog. The Court agreed to hear it on February 23, 2026.

Boulder County and the City of Boulder sued the companies in state court on April 17, 2018, alleging they misled the public about climate change and should help pay for wildfire, flood and other costs. In May 2025 the Colorado Supreme Court ruled 5-2 that the claims could proceed under state law, and the companies petitioned the U.S. Supreme Court that August. The Trump administration, business groups and conservative organizations filed briefs urging the justices to take the case, Bloomberg Law reported.

The Court will consider two questions: whether federal law bars state-law claims seeking relief for injuries allegedly caused by interstate and international greenhouse-gas emissions, and whether it has authority to hear the case at this stage. The companies argue that "Boulder, Colorado, cannot make energy policy for the entire country," while Boulder says the Clean Air Act displaced federal common law without preempting state tort claims.

The stakes reach beyond Colorado: at least 60 state and local governments had brought similar suits as of August 2025, according to a Suncor filing cited by the National Constitution Center. A ruling for the companies could shield them from similar state-law claims, while a ruling for Boulder would let the case proceed in state court without deciding it on the merits.

Argument begins at 10 a.m. ET. A ruling will come later; Monday's questioning on preemption and jurisdiction may signal how broadly the Court is inclined to decide.