It was while waiting for a certain balladeer to play an outdoor concert in Boulder, Colorado, that I first heard Neil Young’s “After the Gold Rush.”

It was a brand-new song in that fall of 1970, sent out over a big sound system to a gathering in a field on a sunny late afternoon. The striking thing was that for all the virtues of the balladeer to come, the crowd’s peak unifying moment had come and gone with the song.

What was left of hippie tribalism was summoned up, along with that perennially muscular engagement with issues that Young has always brought to his music.