First, no number of troops can stop the sort of violence that is going on in Iraq, and the violence will not be stopped without a legitimate government which includes all sides working together. As far as I can tell, that is not going to happen. Perhaps an American military dictatorship would work, but that is not going to happen either.
Second, the increase in violence is NOT because of the belief that America is going to withdraw, as much as that plays a part.
The violence started the day after mohammed died, when Ali was not made leader. It continues to this day, and will always continue until islam dies, as it must die. In Iraq, you are simply seeing true, authentic mohammed-worship in action. To the shia, sunnis are infidels, and vice-versa. Where there is islam, there is violence, and always be violence, because that is what islam requires, with the promise of eternal sex orgies devoutedly believed by the idiotic jihadis.
It is amazing that even conservative writers do not yet grasp this fact.