"For What It's Worth" (Buffalo Springfield)

It's almost ridiculously simple: an understated acoustic guitar playing a single chord, paired with an electric guitar with the tremolo cranked up, playing the same two-note pattern, over and over—plucking the 1, plucking the 5, and then back down to the 1 of the scale.  It doesn't sound like a formula for any kind of hit song.  But that's the structure of "For What It's Worth" by short-lived folk-rock band Buffalo Springfield.
The song was penned and sung by Stephen Stills, who most notably went on to form supergroup Crosby, Stills & Nash after Buffalo Springfield imploded (the result of creative tensions between Stills and bandmate Neil Young and various members getting busted—and even deported—for possession).  Although it's often assumed that the track is a protest song about the Vietnam War, that's not the case.  Stills wrote it after witnessing a run-in between police and students on LA's Sunset Strip.
There were a number of bars and clubs geared to teens and college students along Sunset Blvd.  Various business owners and older residents had grown tired of kids congregating outside the late night clubs, and they pushed to have a "no loitering" ordinance passed, which stipulated a 10 pm curfew.  Students saw this as a violation of their rights, so they took to the street outside a club called Pandora's Box (currently the site of a traffic island, across from a strip mall).  Things started peaceably enough.  But as the number of student protestors grew and they started blocking traffic, that's when the riot squad got called in.  Stills wasn't directly involved in the protest; he'd merely driven through the area, saw the tense situation, and turned right around and headed home, where he came up with the music and lyrics in a matter of minutes.
A close read of the lyrics reveals that it's neither explicitly pro-students nor pro-police; it's merely a chronicle of the event by a bystander who can't really comprehend how things got so out of hand.  In short, you have the students marching and holding picket signs on one side because they're pissed off about a curfew, and then police overreacting on the other.  That's why the refrain (I think it's time we stop. Children, what's that sound? Everybody look what's going down) is just as important as the line Nobody's right if everybody's wrong, in my humble opinion.
So it's not a protest song.  But it is one hell of a piece of journalism, set to the funkiest backbeat in all of 60s folk-rock.