For what?
To establish some form of Kurdish state? The Turkish Government, among our stronger allies, will not thank us for this.
To establish Islamic State(s) in the Arab regions of Iraq? Probably difficult to sell this to the American people as “victory.” Certainly an odd aspect of our “War on Terror.”
To establish a Shiite State in southern Iraq? Good news for Iran, a charter member of the “Axis of Evil.” Bad news for Iraq’s southern neighbor, Saudi Arabia, most of whose oil fields lie in Shiite tribal areas.
Perhaps we can redeem ourselves by learning lessons of sufficient value.