On an August night in 2017, a mob of neo-Nazi thugs under the banner “Unite the Right” gathered in a park in Charlottesville, Va., to protest the removal of a bronze statue of the Confederate general Robert E. Lee. Although Donald J. Trump, then the president, found no fault with the race-baiting demonstrators, other people did. A counterprotest ensued; the results were explosive.

And suddenly, public monuments commemorating historical figures became prime symbols of the country’s split into violently opposing ideological camps.

That split feels wider than ever now. And although a campaign to reassess the values embedded in monuments followed, spurred in large part by Black Lives Matter, controversies around historical commemoration linger and thinking about new models continues. What forms should they take? What subjects are worthy of honoring? Is frozen-in-time material permanence necessary, or even desirable?

Such questions are posed and resolutely tested in “LaToya Ruby Frazier: Monuments of Solidarity” at the Museum of Modern Art, a two-decade midcareer survey of an American photographer and social activist who takes race, class and gender, viewed through the intimate lens of family and community, as her focus, and addresses them in photographic series presented as variably effective sculptural installations.

Frazier came to photography young. Born in 1982 in the industrial town of Braddock, Pa., a short distance from Pittsburgh and the site of Andrew Carnegie’s first steel mill, she picked up a camera in her teens. By that point Braddock’s days of promise and prosperity were long past, with a predominantly African American remnant population left stranded. Jobs were scarce; pay, low. Schools were foundering. The only hospital was on its way to being shuttered, a catastrophe in a town plagued by the effects of unregulated, health-ruining industrial pollution.

From a few outdoor shots in the show’s opening galleries we get a clear sense of the environmental wreckage Frasier moved through growing up. And from interior shots we understand how a commandingly observant young person survived and thrived, thanks to the protective company of two women, her grandmother, Ruby, and her mother, Cynthia.

Her grandmother, who raised her, was herself an inventive, if undeclared, artist, judging by the altar-like assemblages of dolls and figurines that appear in Frazier’s pictures. And her mother, employed as a nurse’s aide and bartender, actively collaborated in Frazier’s earliest photographic and video work, forming the first in a line of female creative partnerships the artist would forge over the years.

Frazier’s pictures of both women are among the most unguardedly personal she has made: shots of her grandmother at the end of her life, and of her debris-strewn living room after her death, have a reliquary tenderness impossible to forget.

These early autobiographical photos, several of which appeared in the 2012 Whitney Biennial, launched Frazier’s career and defined her trajectory as a justice-minded documentarian of Black working-class life. Opportunities for further projects soon followed.

In 2015 she traveled on an assignment by Elle magazine to Flint, Mich., another impoverished Black city, this one a victim of environmental poisoning through what amounted to a government-mandated polluting of its water supply. There Frazier initiated a second collaborative partnership, with two women, Shea C. Cobb and Amber N. Hasan, both local workers and artist-activists, around whom she built a powerful photo essay titled “Flint Is Family in Three Acts.”

Its narrative, which unfolds over four years, opens with a video, set to rap-style poem written and performed by Cobb, documenting the water crisis in Flint, and the protests in response to it. Frazier then tracks Cobb’s brief retreat to the safety of a family farm in Mississippi. (Hasan made a similar short-term move, to Puerto Rico.) And the story concludes on an upbeat note — here the photography changes from black-and-white to color — when the two women join forces with other community members to bring to the city a generator that produced clean water almost literally from thin air.

Frazier then photographed Flint residents in front of the hulking machine, some triumphantly smiling, others patiently posed with water jugs at the ready. In a format she would thereafter regularly use, the portraits are accompanied by printed interviews, with pictures and texts displayed atop steel stands arranged in free-standing V-for-victory formation.

Frazier pushes a sculptural dimension further in two installations she calls “Monuments to Workers.” One is a shout-out to a group of community health care professionals who stayed on the job in Baltimore during the mortal siege that was the Covid pandemic: Their words and portraits, printed on panels attached to IV poles, seem to be floating in place.

The second worker piece emerged from Frazier’s documentation of the forced closing of a General Motors plant in Lordstown, Ohio, that produced the now discontinued Chevrolet Cruze. Here too she photographed and interviewed on-the-ground personnel, dozens of United Auto Workers union members — Black, Latino, white — who were fighting to keep the plant, so central to their lives, open. And at MoMA she gives their images and words a symbolically resonant display: in a long, shed-like steel structure evoking both an assembly-line frame and a buttressed church nave.

And the show — organized by Roxana Marcoci, senior curator and acting chief curator in the department of photography, with Caitlin Ryan, an assistant curator, and Antoinette D. Roberts, a former curatorial assistant — has two small shrines. A dimly lighted oval space midway through is a walk-in homage to the artist, writer and educator Sandra Gould Ford who, while employed for years in a Pittsburgh steel mill, photographed and archived half-buried documents, including employee grievance reports and records of work-related fatalities.

The exhibition’s final gallery functions as a pilgrimage chapel dedicated to the Chicana activist Dolores Huerta, a founder with Cesar Chavez of what became United Farm Workers. In 2023, Frasier visited Huerta, now 94, photographing her at sites related to the California labor movement and in the company of her large extended family. Photographs of the visit are here, surrounding a life-size portrait of Huerta that dominates the space like a devotional icon.

All these installations from the past decade, with their sculptural and architectural features, are commemorative monuments, but monuments to the living, to social and political realities in progress. They’re far less about what once was than they are about the present and future: what is, and what will and should be. As such they are dynamic: provisional, revisable, correctable. And without exception, they’re dedicated to people who, in ways modest or epic, have turned their energies toward a common social good, as, in Frazier’s view, artists should be doing.

The recent work has some problems. Accessibility is one. The printed texts that have become an intrinsic part of Frazier’s format are, for reasons of length, difficult to take in. It’s likely that even the most conscientious viewer will only sample them.

Nor are all the photographs equally eye-catching. Compare Frazier’s shots of her family in the Braddock series with her recent ones of the Huerta family and you instantly see a difference in intensity. In the early images the artist is a fully embedded emotional participant; in the later ones she’s a documenting tourist.

But these are minor flaws, of the kind that any serious monument-builder working on the tough joint tasks of truth-telling and healing, must tackle and resolve, again and again. Frazier is such a builder and, in our present thug-threatened moment, a needed one.

LaToya Ruby Frazier: Monuments of Solidarity

Through Sept. 7. Museum of Modern Art, 11 West 53rd Street, Manhattan; 212-708-9400, moma.org.