This editorial from The Economist supports continued American presence in Iraq while calling it a choice between "the disastrous and the unpalatable". It is not hard to guess that the reason given is that withdrawal would lead to worse violence than there is now. They acknowledge that it might already be too late, that American soldiers may well be dying to no good purpose, that Iraq may be too far down the road of scission. However, they say, "it is not possible to be sure of that yet".
This is by no means a dispicable argument. In a position of ignorance, you weigh up the probabilities and come to the conclusion that the least worst, for the moment, is to hold the course.
Yet the editorial's field of reference is curiously narrow: Iraq and American public opinion (plus that dubious BBC/ABC poll). They do not consider the effect of precipitate American withdrawal in the broader landscape of world order. If the one sherrif/policeman in town goes down to the outlaws, the dictator-wannabes, if Jihadists world-wide can celebrate a victory, then we will all suffer.
Not only that, but to leave one of the world's most important sources of petroleum in the hands of whoever can get their hands on them would be the height of irresponsibility. The original idea was that a working democracy in Iraq would shake up the stultifying and disaffected states of the Middle East. It would have. But if that's no longer possible, then leaving Iraq in chaos would shake them up even more, and not in a way that we, or they, would welcome. The first target of the Jihadists is the Arab states; we only come second. If we can't make the Middle East better, let's not make it even worse. Give Petreaus a chance.
Having said all this, there does remain a Big Question: what is the end game we are fighting towards? What is the best possible result, for Iraqis and for us? What is the strategy geared to work towards? Questions posed here at the Small Wars Journal, and ones I don't know the answer to.