The “major questions” doctrine is likely to substantially affect environmental law. The “major questions” doctrine provides that for “major policy question[s] of great economic or political importance, Congress must either: (i) expressly and specifically decide the major policy question itself and delegate to the agency the authority to regulate and enforce; or (ii) expressly and specifically delegate to the agency the authority to both decide the major policy question and to regulate and enforce.” As we noted in our last post touching on the “major questions” doctrine, we expect that the “major questions” doctrine may be a focus of other cases on the docket this year including a pending case involving U.S. Environmental Protection Agency greenhouse gas regulations.