“Community organizing” is a phrase that’s taken on an almost elastic quality in this fraught political moment. When it isn’t being wielded by right-leaning ideologues to slight grassroots politics (see the 2008 US presidential and 2025 New York City mayoral elections), it’s being embraced by progressives who believe that hopscotching among major protest movements and voting every four years will eventually turn the tide.

But lost in the back-and-forth is a basic truth: the most effective community organizing is as much art as it is science. “Talk to younger [activist] groups, and they say: ‘Oh, we do things online’ – and some of them get this kind of burst of attention,” says Raymond Telles, a venerable documentarian with a 35-year history of following people-powered movements for PBS, ABC and other US networks. “But it doesn’t last. There isn’t that person-to-person follow-up. You can’t just demonstrate and be a flash in the pan. You’ve got to stick to it.”

Telles’s latest film, American Agitators, is a no-frills, old-school documentary that pays tribute to Fred Ross Sr, the activism godfather fondly remembered by those in the struggle as a “social justice arsonist” who approached the work as a methodical effort to “light people on fire”. For more than 50 years, until his death in 1992 at age 81, Ross mobilized communities to fight segregation and expand voting rights, while helping to build labor movements across the country.

Ross didn’t just write the manual on contemporary activism – Axioms for Organizers, a scrapbook of wisdom dating to his early years as a Depression-era social worker assigned to the same Coachella valley immigrant labor camp that inspired John Steinbeck’s The Grapes of Wrath. He passed down lessons learned from his mentor, the progressive firebrand Saul Alinsky, to farm worker leaders Cesar Chavez and Dolores Huerta, and played a foundational role in the political ascents of Nancy Pelosi and Dianne Feinstein. Then he passed the baton to his son, Fred Jr, who extended the family’s activism into campaigns to stem the flow of US military aid to rightwing forces in Central America.

Telles had been circling Ross’s legacy in his many films on race, labor movements and Latino heritage over the years. He filmed Ross’s memorial service for his 1997 documentary The Fight in the Fields, a Chavez biopic. It wasn’t until 2021 – after decades of gentle nudging from Fred Jr, who was keen to preserve his father’s legacy on screen – that Telles finally went ahead independently with American Agitators, a major departure from his usual network-led path to production. Quite quickly, Ross’s friends and former collaborators stepped up, raising $1m for the project.

The only regret is that Fred Jr – who died of pancreatic cancer in 2022, just as principal photography on Agitators had wrapped – didn’t get to see the 95-minute final cut or hear his voiceover work throughout. “He and I would meet every week and strategize,” Telles says of Fred Jr, who really pushed for the film’s third act to focus on the future of organizing. “His guidance was really important in terms of looking for the groups that really had legs.”

At a glance, Ross would not seem an obvious champion for the destitute and disenfranchised peoples of the 20th-century US. Tall, slender and bespectacled (picture Gregory Peck as Atticus Finch), Ross didn’t just stand out among the fields and factions where he was sweating to rally support. He looked, for all the world, like a narc. “I was kind of set back a little bit when I saw him,” Huerta recalls of meeting Ross as a 25-year-old schoolteacher. It’s a wonder anyone in the Black, Latino and Asian communities he worked most closely with in California even spoke to him, let alone opened their homes to him for organizing efforts around better working conditions, education and more equitable treatment under the law.

In reality, Ross turned his formative years in the federal government into a blueprint for confronting power. Time and again, Agitators shows him converting his skeptics with bottomless empathy, an unwavering commitment to their causes and an unerring track record of community organizing successes – all without seeking much in the way of credit or spotlight. Ross’s rallying efforts helped resettle Japanese Americans who had been sent to concentration camps back into the mainstream workforce, and secured a courtroom victory for seven Latino teens who were brutally beaten by Los Angeles police in an incident known as Bloody Christmas.

His campaign to desegregate California schools helped lay the groundwork for the supreme court’s landmark decision in Brown v Board of Education. “He had a plan and drove people crazy with the fact that he was so disciplined,” Telles says, channeling his principal subject. “‘This is what you do. You have to follow up, keep track.’ He was so meticulous.”

Ross’s intensity helps explain Pelosi, specifically how the daughter of a Democratic machine boss from Baltimore won a northern California congressional seat en route to becoming the first – and so far only – female speaker of the House, where her personal touch proved essential to vote-counting and fundraising efforts. “One thing you have to understand about Fred Ross Sr and Fred Ross Jr: if you engage their leadership and their services, you must honor their direction,” Pelosi says in the film.

Huerta is another prominent character witness in Agitators, a spirited advocate for Ross and the kind of collective action that has kept her going well into her 90s. She remembers being active in the Girl Scouts, church clubs and other groups meant to unite neighbors in common cause – and coming away disappointed. “They never really had any answers to any of the real issues that were affecting the community,” she says.

At no point, Telles says, did Huerta intimate to him or anyone else in the film-making that she was about to go public with sexual abuse allegations against Chavez, including two incidents that led to children she later put up for adoption – a bombshell revealed in a years-long New York Times investigation into Chavez’s abuse of girls and women.

In a statement, Huerta said she had stayed silent out of respect for the farm worker rights movement and the decades of service that built her outsized reputation in activism. “We were with her the day before, spent the whole afternoon with her,” Telles recalls. “She didn’t let on anything. She’s a sphinx. But she’s an old hand at this. When [the farm workers union] was negotiating contracts in the 60s and 70s, Cesar wasn’t the one doing the negotiating. She was. She was the toughest one out of all of them.”

The revelation had Telles scrambling to make late revisions to the documentary – not least scaling back Chavez, Ross’s most prominent protege. (Ross also wrote the book on Chavez.) An opening title card – “successful movements are never about one person” – establishes the film’s intent to walk the line between acknowledging Huerta’s account without diminishing Chavez’s inextricable role in Ross’s broader story.

The words could almost be read as a scolding from the great mentor. “The film was not about Cesar, but we can’t erase Cesar,” says Telles, who remains in touch with Chavez’s son Paul, the longtime lieutenant who leads the Cesar Chavez Foundation. “[Paul] said the family is having a really tough time. He was going to show up for a fundraiser for us and said: ‘Look, I can’t do it.’”

If anything, the complications around Ross’s legacy make it more important to revisit his legacy now, when a new generation is rethinking what movement-building looks like as threats to workers’ rights and civil liberties grow more intense and sophisticated. Recent victories by Oakland teachers and Las Vegas culinary workers that are highlighted in the documentary suggest that the old methods – hearing out concerns, maintaining focus, following up with everyone about everything – not only still have their use, but can be strengthened by today’s social media tools. It’s simply a matter of digitizing the personal touch.

The dream is for Agitators to become the manual that makes community organizing more of a loaded term, a tinderbox for a new generation of social justice arsonists. Telles still has hope. “I’m hoping that people get inspired and say: ‘Hey, yeah, I guess I can do something,’” he says. “I think people are looking for that right now. I’m hoping this is the right time, and people see the value in Fred Sr’s story.”

• American Agitators is in select US cinemas now