1932, Bonus Army. Several killed hundreds wounded.
1970, Kent State. 4 killed, 9 wounded. National Guard opened fire with rifles.
1993, Waco. 76 killed, including 21 children and 2 pregnant women. US Army vehicles used, SOFD-D (Delta forces) on site.
There have been others. Army soldiers will do as they are told until such a time they can figure out they are on the wrong side, but by then many will have died on both sides.
One of these is not like the others.
Kent State - have you read up about it?
I'm genuinely curious. Are you military veteran?