The war power, like any other power too important to vest in a single set of hands, is a divided, separated, shared power. In crude overview: In general, the power to initiate war is Con‐ gress’s and not the President’s. Similarly, the power to exe‐ cute war, but not to initiate it, is the President’s. Each branch possesses exclusive powers that the other may not properly infringe or usurp. But each branch may leverage its war pow‐ ers, and its other constitutional powers, to check the others’ exercise of theirs—or to attempt precisely such an improper usurpation. That is how the separation of powers
