I really doubt that Al-Queda was involved. It doesn't do anything toward their goals. There are two real problems in Iraq.
After some 50 years, the State Department finally figured out that when we 'knock over' a regime, we need to have a plan B for what to do next in these places. We didn't in Cuba, We didn't in Iran, We didn't in Viet Nam, we Didn't in Nicauragua....
The State Department actually did have a plan in place, unfortunately the management was turned over the Defense Department who didn't have any sort of plan , or experience. The State Department and their planning was left on the sidelines.
It is like we never learned the lessons of Cuba, Iran, Viet Nam, or Nicaragua just to name a few.
Problem 2 is Islam doesn't recognize suicide, and what we have failed to do is to make these people scared of dying. There is a simple solution to that problem, but having worked for our current Secretary Defense some 25 years ago, I can tell you that if the idea didn't come from him, it doesn't have a prayer. Donny boy is a smart cookie, the problem is he takes advice from no one, so the learning curve tends to leave a lot of dead bodies.
What we need to do is to use Islam's own beliefs against these people. For example if die while contaminated by any part of a pig, you are not going to paradise, whether it was in Jihad or not. This creates a very obvious opportunity. We shoul equip the A10's with heated spray tanks, so that lard can be sprayed on battle fields during a fire fight, and all ammunition should be dipped in pig fat at some point in the manuacturing process. In other words, if you are killed by US ammunition, you are not going to Paradise. Now these people will be scared of dying, since you have to be 'decontaminated' before death, if you die with pig fat on you, the Quoran says you are 'screwed'....
You want to protect the US bases from sniper attack? Create a pig area around them. simple, cheap, effective, and it works because we have mobilized the same relgious fervor that is getting us killed, to protect our forces. It has the added benefit of being non-lethal in and of itself.