good point

Juan Cole on the SOFA 2011 withdrawl date:

Whether the U.S. withdrawal will allow a resurgence of violence is a question we can't know the answer to. But it should be pointed out that, while the United States has been there, tens of thousands, if not hundreds of thousands of Iraqis, have died in violence. Entire cities have changed their social complexion through violence. There's been ongoing killing and destruction.

So the U.S. presence has not been a guarantee of social peace in any case.