From a "senior U.S. military official" in Iraq, commenting on the increased sectarian violence in Baghdad a few weeks before the upcoming election:
All we're doing is setting the clock back to 2005. The militias are fully armed, and al-Qaeda in Iraq is trying to move back from the west. These are the conditions now, and we're sitting back looking at PowerPoint slides and whitewashing.
I don't think there's any way to sugar coat this: this was always a possibility, no matter how long we stayed in Iraq. The Four S's (Surge, Sadr, Sectarian cleansing, Sunni awakening) gave Iraq a bit of breathing room, but they didn't change its culture overnight. We still have a bit of influence, and our troops are still available as backups, but at this point the future of Iraq is up to the Iraqis. Surge or no surge, there's no guarantee it will have a happy ending.