re: You're a bit mixed up on this Tom
I would actually agree that al Qaeda and remaining Baath party elements are not currently cooperating on a meaningful level.
The UN compound that was bombed in Baghdad had the same Iraqi guards as before the war. I.e., the same Baathist minders were inside the building. Those guards are no longer there.
Whoever bombed the UN compound, and I think it was al Qaeda, exposed what amounts to a Baathist spy ring. Not exaclty coordinated action.