What is preventing civil war in Iraq?

Not, it seems, U.S. troops. Supporters of the occupation have been saying that we need to keep our troops in Iraq to prevent the country from plunging into civil war. But during the recent violence, our troops have kept a low profile. The Sunnis have been drawn back to the negotiating table partially by diplomatic pressure, but mostly it seems by the simple realization that civil war would really suck. Really suck as in this picture from the New York Times article on the recent violence.
The Times' caption: "In Baquba, a father helped his wounded son Sunday after gunmen fired on boys playing soccer, killing two."

It's going to take a lot of talking to avert civil war, but its clear that the occupation, the nightime raids, and the secret prisons are at best superfluous in healing the country.