I understand that is what a sensible person would do. But what other business does he have?
Agenda Item #1: Hate Bush
Agenda Item #2: Defund the war
Agenda Item #3: Hate Bush
rinse and repeat.
With two failed cloture votes, largely due to Republicans, and his denial that this is a Democratic Bill, he's got all the political cover he needs to table this thing and move on to what he cares about.