Recently Sen. Bob Corker, the Tennessee Republican who is retiring, became an exception that illuminates the depressing rule. He proposed a measure by which Congress could retrieve a small portion of the policymaking power that it has, over many decades and under both parties, improvidently delegated to presidents. Congress has done this out of sloth and timidity — to duck hard work and risky choices. Corker's measure would have required Congress to vote to approve any trade restrictions imposed in the name of “national security.” All Senate Republicans worthy of the conservative label that all Senate Republicans flaunt would privately admit that this is conducive to sound governance and true to the Constitution's structure. But the Senate would not vote on it — would not allow it to become just the second amendment voted on this year.