The traditional way to get your soldiers to kill their own is to bring in troops from a very different region; that's how China does it, and that's the way every despotic government has done it. Wouldn't work in the U.S.A.

Even if you grabbed a platoon of good ole boys from the backwoods of Arkansas and asked them to fire on civilians in San Fran, I doubt they would do it. Our culture is too mixed, you just don't see the same regional differences that you have in, say, Kenya or Malaysia.