Obama's line about Iraq has been: It is a failure, a disaster, and the Iraqi Army will be on its feet next year, and the country will stable--we should pull out as soon as possible.
McCain's line about Iraq hs been: It is a slow, tough success, and the Iraqi Army will be on its feet next year, but it's not ready, won't be ready for a long time--let's wait to pull out.
The arguments for each of them have self-defeating qualities. For Obama, insisting that Iraq will stand and that the Iraqi Army can take over during a 16-month pullout defeats much of the punch in his claims that the war has been a disaster. He admits serious success and progress in saying that the Iraqi Army will be able to take over next year, and hampers his own ability to criticize the Republicans.
McCain, on the other hand, contradicts his own calls for an extended stay by saying the situation is good and improving, that there has been success. Why keep the troops there, if the Iraqi Army is almost ready to go? McCain's stance is a bit more "flexible--" he wants to keep troops there "based on conditions," but this largely means he is largely dodging the problem of having a position altogether.
And Obama, of course, is sticking to his timeline, even before meeting with Iraqi commanders. McCain refuses to have a solid answer, and Obama is back to refusing to alter his based on pretty much anything.
Maybe that's why the Iraqis are taking matters into their own hands.