In a majority opinion authored by chief justice John Roberts, the justices ruled that in the latest example of Democratic overreach, the Environmental Protection Agency was not specifically authorized by Congress to reduce carbon emissions when it was set up in 1970. The ruling leaves the Biden administration dependent on passing legislation if it wants to implement sweeping regulations to curb emissions.

The opinion from the court's conservative majority said that "a decision of such magnitude and consequence rests with Congress itself, or an agency acting pursuant to a clear delegation from that representative body". The justices added they doubted Congress intended to delegate the question of "how much coal-based generation there should be over the coming decades, to any administrative agency".