This may be a blessing in disguise. The Muslim Scholars Association, a hardline, highly-influential Sunni group, has offered their participation in the government if US troops set a timetable for withdrawal. It's a demand we obviously can't meet as is, but were the Shi'as and Kurds to announce that the path was now for the Iraqis to chart and a united, clearly-autonomous Iraq was necessary for that, it'd leave us with no choice in the matter. Indeed, the best thing that could happen to us would be for the democratically-elected government to offer us a dignified withdrawal in the context of proving their autonomy, maybe pairing a timetable (for Sunni dignity) with conditions for implementation (for American dignity). We're too hardheaded to leave any other way, and the Sunnis are too defensive to join a government that we're involved in, so it may fall to the Iraqi-elect to chart a middle path between our competing egos.
That, after all, is what governments are for, right?
I should note that the MSA has other demands too, including full release of detained Sunni prisoners. That's obviously unacceptable, so long as our troops are are patrolling the streets we can't be throwing open the cells of thousands of hardened, recently-imprisoned insurgents. But beyond rejecting the request in the immediate sense, leftover prisoners pose a really tricky problem that we're eventually going to have to solve. Do we turn the insurgents over to the current government? If so, when? What if they want to let a bunch of angry, anti-American radicals out in a gesture of goodwill? It's not something we can really stop, which is why I fear we'll not allow it in the first place. If we were smart, we'd withdraw and ensure that the prisoners can only leave once we do, but we've thus far shown little evidence of being smart .