They already have: SCIRI and Al Dawa.
I do not consider either SCIRI or Al Dawa to necessarily be less dangerous than Al Queda -- for example, the horrific US Marine bombing in Beirut and the US Embassy bombing in Kuwait were linked to Al Dawa, not Al Queda.
Ergo, I'm rooting for them to both lose -- and do not think that the Federal Government should provide Military and Financial support to either. There's no such thing as a "good" terrorist.
If we pull out...and we should...the worst thing that can happen is that the various factions will kill each other.
Practically speaking, that's less that we will have to kill further on up the road. What will happen is two-fold: