If only we had a UN-like body that worked, and a multinational smack-down could come along and knock off the killing of civilians.
I don't care who is serving as POTUS, or from which party, world events do not always allow for a reconvening of Congress - not the fastest body, in any regard - to take necessary actions.
1. Kick China and Russia off of Security Council (might as well fold tents, at that point) 2. Form your multi-national death squads, and send them out.
LV answered this, but to give some background: it was in response to the way Vietnam went down. It was during a time where presidential powers that were quite vast began to be significantly clipped.