Here's a news analysis piece from the New York Times that gives us a glimpse of how Obama will be able to claim that it is he who won the war while delivering the retreat that he promised to the anti-war wing of his party.
From the article:
There always was a tension, if not a bit of a contradiction, in the two parts of Mr. Obama’s campaign platform to “end the war” by withdrawing all combat troops by May 2010. To be sure, Mr. Obama was careful to say that the drawdowns he was promising included only combat troops. But supporters who keyed on the language of ending the war might be forgiven if they thought that would mean bringing home all of the troops.
Pentagon planners say that it is possible that Mr. Obama’s goal could be accomplished at least in part by relabeling some units, so that those currently counted as combat troops could be “re-missioned,” their efforts redefined as training and support for the Iraqis.
Read the whole article. It's actually pretty balanced and points out the revisionism that's going on in regard to Obama's promises on the campaign trail.