Background
Iraq has three major ethnic groups, the Shiites, Sunnis, and Kurds. Under Saddam Hussein's rule, the ethnic tension was contained, but Iraqi society favored Sunnis (despite having less numbers than Shiites). After the invasion of Iraq, violence has escalated massively, with a violent death-toll in the 6-figure range. There is the fear that if the US pulls out of Iraq, the ethnic tension will spiral out of control.