Why are you changing your words?
> against their own citizenry
Germany, 1930s. Cambodia, 1970s.
> You mention Kent State, but that actually illustrates to my point.
It flatly doesn't. US armed forces fired on citizens. No US military stopped them. The second amendment didn't stop them, or cause them to hesitate. The idea that the second amendment will change anything about the US military's response or choice to follow any orders they're given no matter how reprehensible or obviously evil (My Lai, Abu Ghraib) is laughable fantasy, based on a bunch of people who want to dream about being heroes and pretend that their 9mm handgun means something.