Don't forget U.S. troop superiority in training, equipment, motivation, morale, etc.
In Victor Davis Hanson's great book,
CARNAGE AND CULTURE, Landmark Battles That Defined Western Power, Hanson describes how the West developed an incredible knack for killing. In this book he describes nine key battles that illustrate the critical elements that defined Western power, including individual initiative, superior organization and discipline, access to the best weapons and tactical adaptation and flexibility.
While I was reading Hanson's book, the thought occurred to me that the Iraqi’s don’t have a chance, even if they are stupid enough to use gas, bio weapons or whatever. Their culture completely limits them because they lack the critical elements for success in battle, (and life) mentioned above. That is the reason middle Eastern cultures are becoming smaller and smaller in the rear view mirror of the West.