Phil Carter posts about a recent incident that disturbed me when I first heard about it: an Iraqi Army unit tasked to quell the uprising in Falluja took some fire, or was in some way confronted (the details are unclear) by Shi'a in Baghdad during their route march, lost unit cohesion, refused to fight and returned to barracks. It is, as Phil discusses, very difficult to get good men to kill others, and this is compounded when those others are the soldiers' fellow citizens. It's a manifestly good thing that this is difficult; I don't think we'd want to see sociopathy elevated to a cultural phenomenon among any military (and to be sure, there are some where it has been done).
That said, it's also important to have a force capable of fighting societal enemies. In the case of the Falluja battle, it's pretty clear that there are local Iraqis (lawbreakers, for want of a better word) as well as a cadre of foreign jihadis, so there is a mix of foreign and domestic enemies involved. The best way to tackle that kind of mix is to start by defeating the fighters, then send in law enforcement to arrest the enablers, and the locals who ended up not fighting (or escaping the fighting). But that only works if the Army is willing to go in and take out the armed insurgents, because the law enforcement forces would be outgunned (or equally-armed, but restricted by rules of engagement that would prevent their being more effective than those they are trying to subdue).
So in Iraq, we will likely end up falling into a model 180 degrees away from Viet Nam. Near the end of the Viet Nam war (actually after Tet offensive in 1968), the Viet Cong (local insurgents with outside reinforcement and support) were depleted to the point that the ARVN (S. Viet Namese army) was able to defend the country against both VC and the insurgent N. Viet Namese forces that did most of the fighting. The US did fight against the insurgents, but our primary role in S. Viet Nam was to prevent the North from invading with their full army, a situtation the South couldn't handle alone. With the betrayal of S. Viet Nam by the post-Watergate Democrats in Congress (who refused to support S. Viet Nam according to the terms of the Paris agreement that ended US involvement), the North Viet Namese army invaded and defeated the South.
In Iraq, it looks as if the Iraqi army might need to be deployed to protect the borders, while the Iraqi police forces clean up the insurgents, with backing from the US military anywhere the insurgency is active fighting (as opposed to recruitment and incitement). It will be interesting to see how this affects long-term strategy, and I think Phil's take is half right:
I think this is a pretty strong indicator that (1) we cannot turn over sovereignty until we have crushed the most dangerous parts of the Iraqi insurgency and (2) that we must leave some force in Iraq to continue the fight until the Iraqis can build a viable force.