But that is besides the point: the US can do nothing in either case. Iraq is a loss. The question is how much worse the Americans' want to make Iraq which is pretty hard because the first hand accounts I am getting from my Iraqi friends is expressed in tears not in sentences. I say again: Iraq is lost for at least one if not two generations. The longer the US stays the longer they delay consolidation and reconstruction.
[WS:] I generally agree with your assessment - Iraq is a disaster no matter what happens next, which btw should be a good reason for trying Bush and his administration, who single handedly created that mess, as traitors and war criminals.
However, the withdrawal of US troops may have a similar effect to that following the withdrawal of the Soviet troops from Afghanistan. It may lead to the establishment of regime that will pose a far greater long term danger than the current instability. Due to Iraq geographical location, that danger to international community may be far greater than that ever posed by the Taliban regime in Afghanistan.
Another thought - increasing the number of US troops in Iraq may not make the situation any worse than it is now, but it will certainly increase the public opposition to the war. This may have a beneficial effect of reining the hawks in Washington in for some time to come, judging from the experience of Vietnam. A quick and relatively painless pull out may not sufficiently suppress the appetite for military adventurism elsewhere.
Wojtek