Historical Fact:

The Shiites of Basra and other areas in Southern rose up in revolt against Saddam Hussein in 1991 at the end of the war. Unfortunately, the allied forces failed to support them and they were slaughtered by Saddam's forces.

After enduring 12 more years of Saddam's reign of terror, it's quite clear that the only thing keeping the Shiites from rising up in revolt again is the dread fear of Saddam, and his SS troops terrorizing the civilian population. These people have been burned once, and they are understandably hesitant to risk everything again unless the're certain they won't be abandoned to suffer the same fate again. Once they're sure Saddam's regime is doomed, they will rise up.