"The president does not need congressional approval for limited military interventions, and the executive branch has not sought it in the past."
http://www.washingtonpost.com/world/...fd5_story.html
etc. Not worth debating, it's not required, but he wants it. And no matter what, he'll be doing the wrong thing, amirite? yawn
edit: "The president called them into the Oval Office Friday night to tell them two things: that he's now decided to use military force, but also that he was reversing course and would seek congressional approval.
His reasoning, according to officials who were in the room? He wants members on the record, rather than simply criticizing from outside whatever action he takes."
http://www.cbsnews.com/8301-18563_16...on-the-record/