IMHO, I think it depends on how you define victory. Right now, the American home front reminds me of the early 1970s, and it looks like we have two tigers by the tail, i.e. Sunni Arabs and the restive, majority Shi'ites backed by Iran, looking to exploit any chance to obstruct our ends.
The goal of a democratic Iraq is unlikely with needless killing. We need to kill only the bad guys.