Any war. World war II (from the German perspective), Vietnam (from American perspective), Iraq (from American perspective), for example. You have to assess culpability in light of what was known by whom at the time. I don't think buddy-grunt goes into a lot of analysis about it, but when it comes to, say hunting down Jews in the streets and herding them into cattlecars to be gassed in your own country, you should use your own mind and think 'hey, this doesn't seem right'.
I don't think the soldiers who fought in Vietnam had anything like as obvious a sign that things might not be right, and I don't think the soldiers in the current engagement have had.
Edit: I'm not saying whether a war is right or wrong, I'm talking about moral culpability of the individual person in a war.
Dennis