If we are going to use your strategy then we might as well nuke the entire middle east because he'll attract them forever.
Well, if you want to expand the scope of the solution to the entire ME, then yes I'd agree that an opening salvo of five very high yield nukes (Cairo, Damascus, Mecca, Medina, Tehran) would be appropriate. As far as Iraq itself goes, it costs the enemy a lot of resources to put a man in there, and gets them very little out of it. So while we're still fighting, guys like Sadr suck the life from the enemy.
Read up on how Algeria and Peru defeated their terrorists!