Pick an alternative
Jerry Pournelle covers all the eventualities and does a good job of laying out his opinion on each.
The following was (and still is) the goal I had in mind. If we didn't have a workable plan, it should have not been undertaken.
Occupation of Iraq to rebuild it as a Middle East Republic. This is the President's hope, and his dream of his place in history. It is possible, but it is not possible with conventional armed forces. Armies break things and kill people, and if they can't do that, they will lose. But that does not build nations. Nation building would require recruiting an entirely new occupation army. The real army would stand by to defeat serious organized attempts to overthrow the nation builders. The nation builders would operate from entirely different principles, more like police and constabulary than armed forces.
Pournelle
The final outcome of the war on radical Islam may yet prove that Iraq was perhaps a foolish but earnest effort to save millions of lives.