The fact that Congress is currently abdicating its responsibility does not mean that it is actually powerless. Technically, Congress has tremendous powers if it chooses to wield it. SCOTUS can try to rule a law is unconstitutional but Congress can impeach and remove justices at any time. Of course, we hope Congress members will pay the price when it comes time for reelection but at the time of this decision, as long as they can somehow remain united, Congress reigns supreme.