The 6-3 decision limits how far the executive branch can go in forcing new environmental regulations on its own.

„Capping carbon dioxide emissions at a level that will force a nationwide transition away from the use of coal to generate electricity may be a sensible ‘solution to the crisis of the day,’ But it is not plausible that Congress gave EPA the authority to adopt on its own such a regulatory scheme in Section 111(d),“ Chief Justice John Roberts said in the Court‘s opinion, referencing Section 111 of the Clean Air Act.