>That's highly optimistic. I would say that history does not generally support the idea that militaries in general, or the US military in particular, are more reserved when dealing with a perceived internal existential threat than they are fighting overseas.
That's... Not exactly true. History has actually shown the contrary, WASP are usually very soft on other WASP while bloody on everybody else. Examples:
-The US civil war is a perfect sample. I don't think you could find another battle in history but Gettysburg were opposing armies of many tens of thousands fought with just one civil casualty (and an accident, this one). Usually, after a battle is won there is this period of pillaging, raping and general dead and destruction. If you want to see how a real after-civil-war-repression looks like, look at what Cromwell did in Ireland, it's the stuff of nightmares. (Which also supports my argument, because he was very soft on his British opponents).
-There is also the anglo-american war of 1812. The British "sacked" Washington, with, again, only 1 (ONE!) casualty. I mean, come on, it's like they weren't even trying. For contrast, look at what a real British occupation looked like at the time with the suppression of the rebellion of the Sinhalese in Sri Lanka in 1818.
My point: If the US start killing each other seriously, that would be a new in history.