I remember sometime in the early 90s reading about a new psychological test being conducted on at least some Army personnel, that was specifically aimed to determine how they felt about doing things like disarming American civilians, firing on American civilians, and such. I don't doubt that there are elaborate plans already in existence for use of the military against the American people.
On the one hand I don't doubt that the average serviceman is more conservative than the population at large, but I also don't doubt the huge majority will "follow orders".