Sens. Clinton, Dodd, Obama and former Sen. Edwards - to maintain credibility - would be well advised to continually explain how the dramatic changes in Iraq since the war began and how the President's ineffectual policy caused them to change their votes. Do they want to be viewed as putting troops in harm's way and then not protecting them?
Kerry fell into this trap in '04 when he first supported, then opposed an $86 billion Iraq appropriations bill. The fatal statement where he voted for it before he had a chance to vote against it. Kerry went into a too-long explanation of how $20 billion was purely discretionary spending. Bush, in one debate, stated, "It's about protecting the troops. What's so complicated about that?"
Candidates beware - K-I-S-S - Keep It Simple, Senators.