Actually, there are LOTS of classes and tests on what constitutes the law of land warfare, competent authority, etc. in the military -- way better than anything at MIT or Harvard that I encountered. Yes, these are simplified for junior enlisted personnel ("do this, don't do that", vs. why), but for officers and NCOs it probably goes far beyond what anyone in civilian government, outside the judiciary, thinks about.

Having been in multiple combat zones, I think the US military errs too much on the side of legalism. I actually think the US Government, and especially the military, is the wrong tool for counter-insurgency -- there are a lot of people who just need to disappear, or die colorfully, and it would be better if doing so didn't hurt the image of the US.

(I say this as a libertarian atheist...)

Most of the "rah rah usa usa!" people are not in the military.