Wally McNamee / Getty Images

The rock star Graham Nash had a thought while he watched the “March for Our Lives” gun-control protests led by the survivors of the school shooting in Parkland, Florida, this spring. “We teach our children the best way we can,” he told me this week, “but we have to learn from our children, too, or else we are making a big mistake.”

When he’d had much the same thought nearly a half-century ago, as protests erupted all around him, it inspired him to write his classic anthem, “Teach Your Children.” This time, the resurgence in grassroots protest against President Donald Trump led him to work with the artist and animator Jeff Scher to produce a new video for the song, linking the social movements of the 1960s with the proliferating protests of the present day. But while the video convincingly draws parallels, it also highlights a key difference between the two eras. The relentless polarization of the political landscape since the 1960s has rendered social movements more partisan—changing both their tactics and their goals in the process.

In 1968, when he started the song, Nash was still a member of the bouncy British pop group the Hollies. But he didn’t finish it until after he moved to Los Angeles and joined David Crosby and Stephen Stills to create the supergroup Crosby, Stills & Nash, known for its silky harmonies and intricate lyrics.

It was his interest in photography that indirectly inspired him to complete the song, Nash said. Nash collected photographs (and was an amateur photographer himself), and after CSN’s first album hit big, a college museum asked him to provide some works from his collection for an exhibit. When Nash visited the hall, he found the gallery had paired two of the most striking images he owned: a famous Diane Arbus photo that showed a child holding a toy hand grenade in Central Park and an Arnold Newman portrait of the Krupp family,  German arms manufacturers. “Images talk to each other … and when I saw those two pictures together, I realized if we didn’t teach our children a better way of dealing with our world, we were in deep trouble,” Nash told me. “And that caused me to finish that song.”

By the time Nash finished writing, Neil Young had joined the group, which was renamed Crosby, Stills, Nash & Young. The last piece clicked into place when Crosby convinced the Grateful Dead’s Jerry Garcia to play pedal steel guitar on the track. “Even though he had only been playing it a very short time and, I believe, had never played it on record,” Nash remembered, “Jerry loved the song and he brought his pedal steel into the studio and that was his first take.”

Garcia produced a buoyant twang that connected the song to American traditions of folk and country—musically grounding Nash’s conciliatory message of generations learning from each other to find a better future. When “Teach Your Children” was released from CSNY’s album Déjà Vu in March of 1970, it became a top-20 single.

For the new video, Nash teamed up with Scher, who divided the song in two. For the first half, Scher painted black-and-white images drawn from iconic moments of the 1960s protests: the civil-rights and anti-war movements; Martin Luther King Jr. at the 1963 March on Washington; African American athletes raising clenched fists on the medal stand at the 1968 Olympics; the shooting of the protesters at Kent State.

For the second half, Scher created color images of today’s signature protests: Emma Gonzalez at the March for Our Lives in Washington; Black Lives Matter marches; Colin Kaepernick and other football players taking a knee; demonstrators demanding an end to the separation of undocumented children from their parents—all punctuated by paintings of a scowling, shouting Trump. In each case, Scher based his paintings on real images, taken mostly from a collection accumulated by his wife, the graphic designer Bonnie Siegler, for her recent book, Signs of Resistance.

The images from the two eras, to borrow Nash’s phrase, seemed to “talk to each other,” visually linking the generations in common purpose and shared commitment. The present echoes, but extends, the past. “The song is so lovely and about halfway through it goes from ‘teach your children’ to children teaching your parents,” Scher said. “So [the shift from past to present] is built into the song. And the parallels that it’s 50 years from ’68 to now are just overwhelming. So it was a short leap.”

In tracing the “short leap” between the two generations’ goals, though, the video is also a reminder of how large a gulf separates the two political environments. The 1960s movements kept their distance from partisan politics, because they found allies and adversaries in each party. Democratic presidents John F. Kennedy and Lyndon B. Johnson launched the Vietnam War; Southern Democratic senators defended segregation. In both cases, many conservative Republicans supported them; but moderate and liberal Republicans joined with many northern Democrats in opposition. “The ’60s and ’70s movements are in a certain sense nonpartisan,” said the Columbia University sociologist Todd Gitlin, a leading student of the era’s protests. “They have plenty of anger to go around at people of every party.”

By contrast, after decades of unrelenting political polarization and ideological sorting between the parties, most of today’s social movements confront a Trump-led Republican Party almost uniformly hostile to their priorities. That’s forced all of these movements to align more closely with Democrats than the earlier generation did with either party. It’s also required them to focus more on incremental electoral and policy change than the broad transformation of cultural values that proved the most lasting legacy of the 1960s movements. “This is no time to be running around flooded with revolutionary zeal if you can’t cope with the immediate situation, which is this never-ending emergency,” Gitlin said.

Nash’s “Teach Your Children” captures, at its most eloquent and guileless, the ’60s hope of discovering a more fulfilling way of living. At this point, today’s protesters would understandably settle for a new speaker of the House.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.