“For What It’s Worth” is about the police crackdown on protestors at the 1968 Democratic National Convention in Chicago. It was written and recorded the next day, if I remember right.

Buffalo Springfield recorded it in 1966. It went to #7 on the Billboard 100 in 1967. It was written about November 1966 protests against a curfew on Sunset Strip (Hollywood.)

Okay, clearly I am thinking about another song, then.

FWIW is routinely associated with those and other similar events. Great song...well-tuned for its era.

I think I may have been gaslit by a documentary about 1968 that I saw in 1993. It went over the DNC riot, and said a song was written, recorded, and published within a week of the event. It then played FWIW. I did a quick web search, can’t find any song that fits that criteria.