It's gonna be a bloody civil war no matter what.
For instance, the Shiites torturing Sunnis in government buildings. That pisses off Sunnis, they will torture Shiites.
In the meantime the Kurds will be used by the US to attack the real Iraqis, and both sides will fight them.
Eventually the Kurds will form their own de facto state, and the Shiites and Sunnis will fight.
No matter what the Bushies do.
Arf