My recollections: When General Westmoreland returned (was recalled?) from Vietnam he was given command of the military district encompassing D.C. Given the threats of riots/insurrections, he requested some impossible number of troops (250,000, IIRC) to handle the possibilities.
I was in a battalion of combat engineers at Fort Belvoir and we were given something of a first-response, riot-control duty for the D.C. area. We weren’t involved in what you relate but were at the Pentagon in October of 1967.
Anyone believing the country is some sort of tinderbox today has forgotten the situation in the latter 1960s and the 1970s.
Yes, we surely had a volatile situation back then. I think that it could very easily happen again. The anti-war crowd has made the effort to rekindle the fire, but doesn’t have the “drawing power” it once did. Two things drew a lot of otherwise uninterested folks to the anti-war stuff back then. Sex and drugs.