I think the RNC has it just about right:

Today, Obama Claimed That He Would Be Open To Listening To Commanders On The Ground And What They Advised Regarding Withdrawal From Iraq:

Obama Told CNN’s Candy Crowley That He Was Open To “Facts And To Reason” With Regard To His Plan For Withdrawal From Iraq. Crowley: “You have said you want to go back to Iraq.” Obama: “Yeah.” Crowley: “See what the situation is on the ground. Is there nothing that they could show you or that General Petraeus could tell you that would move you from wanting to immediately begin removing U.S. troops?” Obama: “Well, you know, I never say there’s nothing or never or no way in which I’d change my mind. Obviously, I’m open to the facts and to reason. And there’s no doubt that we’ve seen si gnificant improvements in security on the ground in Iraq.” (CNN’s “The Situation Room,” 6/5/08)
But Previously, Obama Committed To Removing Troops From Iraq Regardless Of What Military Commanders Advised:

Obama Committed To Withdrawing Troops From Iraq Regardless Of The Advice He Received From Commanders On The Ground. ABC’s Charles Gibson: “And, Senator Obama, your campaign manager, David Plouffe, said, ‘When he is’ — this is talking about you – ‘When he is elected president, we will be out of Iraq in 16 months at the most. There should be no confusion about that.’ So you’d give the same rock-hard pledge, that no matter what the military commanders said, you would give the order to bring them home?” Obama: “Because the commander-in-chief sets the mission, Charlie. That’s not the role of the generals. And one of the things that’s been interesting ab out the president’s approach lately has been to say, ‘Well, I’m just taking cues from General Petraeus.’ Well, the president sets the mission. The general and our troops carry out that mission.” (Sen. Barack Obama, Democrat Presidential Candidate Debate, Philadelphia, PA, 4/16/08)

More here.