The point that is relevant to constitutional war powers is the political imperative of public support for military operations. If there are vital American security interests at stake, the American people will be on board. Congressional authorization and endorsement will then make it possible to achieve crucial military victories.

Americans, however, are simply not interested in trying to democratize Islamic societies through military force. On this score, it is essential that Congress do its job: Demand that any president who lurches into these conflicts seek congressional authorization for clearly stated objectives, and satisfy the people’s representatives that we are pursuing real security objectives, not conducting a sociology experiment at the expense of our best and bravest young people.

As a practical matter, the Constitution may not be able to prevent an overly adventurous president from enmeshing us in conflicts against our interests. But congressional war powers can still have much to say about the legitimacy of the use of force, and therefore about its extent and duration. Moreover, where the use of force is clearly in America’s vital interests, congressional war powers — used to issue a powerful endorsement of a clear, necessary mission — can help us achieve something that has eluded us since 1945: victory.