Good points, with which I agree.

When we look at units of the US Army, we no longer sort them by loyalty. New Yorkers over there! Catholics over there! Afro-americans there! Of course, it took generations to lose those loyalties, but even at the founding there was loyalty to the nation-state.

Without that greater loyalty, building an army becomes difficult. Esp. an army whose primary task is to fight and kill “their” own people -- a vital note usually overlooked in these discussions.

Unfortunately it is worse than just Shiite vs. Sunni. There are equally strong ethnic divisions in Iraq.

I believe the only national Army indigenous to Iraq is the Kurdish Peshmerga. Many or most accounts of effective fighting by the “Iraq Army” are no such thing, but by the Peshmerga fighting Arabs and Turkman. I doubt they are fighting for an “Iraq” state.