In the wake of President Trump’s announcement of the U.S. withdrawal from the Paris climate agreement, the governors of New York, California and Washington state have announced the formation of a “United States Climate Alliance,” which will pursue the policies of Paris through their own joint action.
The alliance faces some potential constitutional challenges and limitations. The Interstate Compacts Clause, article I, section 10, clause 3 provides that “no state … may enter into any Agreement or Compact with another State, or with a foreign power,” without the consent of Congress. Unlike the ethereal foreign affairs preemption doctrine (which I will discuss in a subsequent post), this is a clear textual limit on state power. Despite the Constitution’s clear “no,” the Supreme Court in the 20th century has limited the scope of interstate “agreements” that the provision blocks.