If conventional dramatic biopics grapple consistently with the difficulties of condensing a full and rich life into a reasonable running time, so too do nonfiction films examining a specific person or even a social movement – in their case typically struggling with integrating that focused illumination into a broader portrait of the changing culture at large.

Co-directed by Abel Sanchez and Andrés Alegria, A Song for Cesar brings a unique point of view to the life and legacy of labor leader and civil rights activist Cesar Chavez, who in the 1960s worked tirelessly on a series of campaigns to improve the lives and livelihoods of exploited, overwhelmingly immigrant Mexican field laborers in the United States.

With an interesting and laudable roster of interviewees, which includes Maya Angelou, Joan Baez, Cheech Marin, Taj Mahal, Edward James Olmos and Carlos Santana, among many others, the documentary sidesteps any staid repetition of events and dates. Instead, it focuses on how Chavez’s union-organizing and other activism helped first to birth and then to sustain and benefit from a larger Chicano art movement — most especially within music but encompassing everything else from murals and fine art to theatrical performance.

A Song for Cesar opens with a soulful, evocatively photographed studio performance of its title tune, written by co-director Sanchez and Jorge Santana. From there, the movie segues into a bit of biography on Chavez, including detailing his embrace of pachuco culture. After serving in the Navy during World War II, Chavez would rejoin his extended family and become an agricultural laborer in Delano, California, one of the fertile farmlands of the sprawling state, which remains responsible for around half of all fruits and vegetables consumed in the United States.

Bearing witness to the struggles of the working poor around him, Chavez would join the National Farm Labor Union and focus on organizing. Understanding the value and power of Latinos more assertively telling their own stories, Chavez would soft-commission various cultural works that highlighted his unionizing efforts. Musicians and singers like Daniel Valdez and Agustin Lira, the latter of whom would later pen the social justice anthem “La Peregrinación,” could help spread the message of other striking communities, underscoring the commonality of their problems. Meanwhile, artists like Daniel DeSiga and especially Carlos Almaraz would capture the nobility of purpose in struggling to boost wages and end dehumanizing working conditions. All of these artists, and many others already more connected to the mainstream culture at the time, then also benefited from their attendant raised public profiles at a time of rapid change within American society.

If there’s a criticism to level at A Song for Cesar, it’s that there’s not quite a true and sustained sense of historical sink-in with the film, until arguably a portion more than one hour into its 85-minute running time that spotlights a 25-day march across California and up to the state capital of Sacramento, in 1965. It’s here that the perilousness of Chavez’s work is finally, and very necessarily, cast into stark relief, with footage of growers and other anti-union counter-protestors angrily assailing peaceful marchers.

Instead, most of Sanchez and Alegria’s movie alights upon the connection of its interviewees to Chavez in fitful fashion and avoids laying out a timeline of all his professional efforts. For example, it celebrates the fact that artwork and songs were instrumental in introducing Dolores Huerta, co-founder of the United Farm Workers, to people who had no connection to their movement, but the movie itself (even though Huerta is interviewed) scarcely stops to acknowledge who she was or how she worked with Chavez to advance their shared mission.

A Song for Cesar is thus a bit like the cinematic equivalent of a dragonfly, skimming along the surface of the water. This approach is in some ways admirable — elevating the movement, and not simply one man. But in trying to advance its valid and estimable thesis, it sacrifices some simple connective threading which would make the movie, and its core points, a bit more memorable.

Still, in the end, A Song for Cesar proves a warm, engaging watch. In the same way that human stories enrich and enliven any understanding of dutifully memorized historical dates, A Song for Cesar casts a glance back in time and showcases the correlative relationship between social progressivism and shifts in youth culture and, then, popular culture. It also illustrates, as one interviewee shrewdly notes, that leaders need not come from ivory towers, but can also come from the rocks and soil of those who toil among the common man.