It’s true that declaring war on another country often seems arbitrary as a matter of international law. But that’s a different question from whether the U.S. government is following its internal constitutional restraints in choosing war. The U.S. Constitution is designed to require that Congress take an active role in the decision to go to war — because the great majority of the framers believed that a republic should go to war only when the public supported that action.

via Obama Doesnt Want Your Approval for War – Bloomberg View.