What is the Sabramerican US Iraq policy going forward, in some detail if you would care to? I am the kind of guy that does not waste too much time on sunk costs. Every day is a new day, and one must deal with what is on one's plate at the moment.
The unlikely and untenable position is to "expend" the war to Syria and Iran. Won't happen.
Best of the worst, is to let the Arabs bleed themselves to exhaustion and retreat to support our only allies in the mess, the Kurds.
At the end of the mess, at least at the end of the fighting, there will be a de facto if not a de jure partition.