If I were a smart presidential candidate I'd understand that what I say about Iraq now is not all that important. What matters is what you'll say next January, and if you get the nomination, the following September. I know the press has been willing to call McCain "consistent" despite his ever-shifting pony plans for Iraq, so he might get away with his "if only they'd listened to me" schtick. But that's only the first step. Come January, and the following August, he'll have to say what we should do now.
I really can't see the Republicans divorcing themselves from this.