Supreme Court Dismisses Red State Constitutional Challenge to California’s Tailpipe Emissions Authority

The Environmental Protection Agency has granted California over 100 waivers for it to set various standards, including for zero-emission vehicles.

Cars travel along Interstate 80 in Berkeley, Calif., on Jan. 16, 2024. Justin Sullivan/Getty Images

The U.S. Supreme Court has dismissed a legal challenge by 17 Republican-led states that argued that California’s unique authority to set stricter tailpipe emissions standards is unconstitutional.

With Justice Clarence Thomas dissenting, the high court on Dec. 16 denied an appeal from the attorneys general of Ohio and 16 other states, who in their petition challenged the constitutionality of the Clean Air Act’s provision allowing the Environmental Protection Agency (EPA) to grant special waivers to California to set vehicle emissions standards that are tougher than those in other states.