Will America’s next war be declared by Congress or the president?

GABRIEL GARCÍA MÁRQUEZ wrote that it is easier to start a war than to end it, an observation that might also serve as a summary of America’s experience since 9/11. The constitution vests Congress with the awesome power to declare war, so it is a persistent source of vexation on Capitol Hill that presidents so often drop bombs without asking permission. Yet it is possible to understand why presidents might roll their eyes at that prospect considering how much difficulty Congress is having resolving a far less weighty question: when is it the right time to undeclare a war?