[gravitypunch]

war? As with fragmentation, the U.S. military's presence has, in fact, been a motor for civil war in that country. The invasion and subsequent chaos, as well as punitive acts against the Sunni minority, allowed extremists, some of whom took the name "al-Qaeda in Mesopotamia," to establish themselves as a force in the country for the first time. Later, U.S. military operations in both Sunni and Shia areas regularly repressed local militias -- almost the only forces capable of bringing some semblance of security to urban neighborhoods -- opening the way for the most extreme members of the other community to attack.
It's worth remembering that it was in the surge months of 2007, when all those extra American troops hit Baghdad neighborhoods, that many of the city's mixed or Sunni neighborhoods were most definitively "cleansed" by death squads, producing a 75-80% Shia capital. Iraq is now embroiled in what Juan Cole has termed "three civil wars," two of which (in the south and the north) are largely beyond the reach of limited American ground forces and all of which could become far worse.

The still low-level struggle between Kurds and Arabs (with the Turks hovering nearby) for the oil-rich city of Kirkuk in the north may be the true explosion point to come. The U.S. military sits precariously atop this mess, at best putting off to the future aspects of the present civil-war landscape, but more likely intensifying it.