Mark Kleiman sums it up well:
More Iraqis will probably die of violence just after a U.S. withdrawal than are dying violently now. That will hand the pro-war forces a rhetorical "I told you so." Anyone who can blame what happened in Cambodia on U.S. doves is clearly shameless enough to blame the civil war in Iraq on the people who opposed the invasion rather than those who carried it out and then bungled the occupation.
But that's not a good enough reason to hang around, unless at some point it stops being true: that six months, or a year, or two years, or five years from now we would be able to withdraw and not have civil war and massacre follow. If we're spending blood and treasure only to postpone a catastrophe we can't prevent, the "humanitarian" argument against a fairly rapid withdrawal collapses.
Unless we are making progress towards an Iraqi government capable of preventing a civil war -- and it appears that we are not -- then there will be a civil war and probably ethnic cleansing whenever we leave. The question then is not whether leaving will lead to a bloodbath, but whether staying is simply putting off the inevitable -- but at immense cost to us, militarily, politically, and fiscally.
That a bloodbath would eventually follow the removal of Saddam Hussein has always been obvious. Dick Cheney himself said so in the 1990s and those who opposed this war from the beginning said it in 2002. To blame the inevitable on the people who have been right all along is disgraceful.
Unfortunately, this looks like it's playing out exactly as I predicted at the end of last year:
The administration will smear anyone who suggests we might have to cut our losses and leave. (The dreaded "cut and run.") They'll do so right until there is absolutely no other option. Then it will be an unplanned, "chaotic bugout with huge, avoidable losses of men and materiel." Then they'll blame the Democrats.
If they're responsible, we can minimize the damage we do by leaving. We can set a timetable and do our best to prepare the Iraqi army. We can take other diplomatic and military options to make our inevitable withdrawal less harmful. But they're not responsible. They're going to wait and wait and soldiers are going to keep dying until finally the truth is absolutely undeniable, and then they'll bug out in an awful mess and blame the Democrats.
If the right is so concerned about the results of our withdrawal, the time to start planning for it is right freaking now. We should be talking about the way to withdraw with the least possible damage to Iraq, but instead the Bush administration is forcing us to continue arguing about whether the damn surge is working.
Before the invasion, the administration failed to plan adequately for the occupation and reconstruction. Now they are failing to plan for the inevitable withdrawal. And you just know they're going to blame the results on the Democrats.