Most Wednesday evenings there’s a small but spirited peace protest at the Lake Street-Marshall Avenue Bridge in Minneapolis. At that vigil, a constant since President Bill Clinton ordered bombs to be rained down on Yugoslavia in 1999, you’re likely to find one or more of the four biological McDonald sisters. These nuns didn’t initiate the protests — an activist named Marie Braun was a critical catalyst — but have been fervent supporters ever since.

Just last month, Jane McDonald was there, waving signs at motorists who honked support and displeasure or otherwise made their feelings known. Her sister, Brigid, too, recently braved inclement weather to urge her fellow humans on the path to peace.

“When people drive by and give us the finger, I say, ‘Well, that’s a half a peace sign,’ ” said Brigid McDonald, a peace protester for more than half a century.

“I believe we’re all wounded healers,” Jane added. “I was born into the Roman Catholic Church, but I’m in the roaming church in search of a more liberated truth.”

Folk heroes and icons of peace, the outspoken sisters have led lives of activism against war and injustice. They have been arrested more times than they can remember, helping them achieve near mythic status in peace circles but also bringing unwanted attention. They have been the subject of newspaper articles and even a 2009 documentary, “Four Sisters of Peace.” Now their story, which began on a Minnesota farm, comes to the stage when “Sisters of Peace” premieres this weekend at the History Theatre.

The play is about women who worked in Minnesota but became internationally known, not the least because they went against powers and principalities, including the pope. Los Angeles-based playwright Doris Baizley interviewed all four siblings — including Rita and Kate — to craft a story about these peacenik icons, touching on everything from their histories and choices to their mission and determination.

Sisters of Peace Who: By Doris Baizley. Directed by Barbra Berlovitz. Where: History Theatre, 30 E. 10th St., St. Paul. When: 7:30 p.m. Thu.-Sat., 2 p.m. Sun. Ends April 14. Tickets: $15-$42; 651-292-4323, historytheatre.com.

The sisters are not cloistered, Baizley explained. Because they are part of the Sisters of St. Joseph of Carondelet, an order named for a carpenter, they live and work in the community.

“So their philosophical base is worker nuns,” said Baizley, who has penned a number of documentary theater shows but still was surprised by the sisters’ iconoclasm. “I’d never met such active women, and each of them so individual, so much their own self. It’s contradictory to what we think of when we think about people joining a religious community and giving up your identity.”

Gradual transformation

The McDonald sisters came from a big Irish-American farm family with 11 children in Hollywood Township near Watertown, Minn. Rita was the first sister to join the convent. She’s now 97, with age-appropriate health concerns that prevent her from being interviewed. But she has spoken in the past about what religious life offered.

“In the 1950s, that was a way for women to find more satisfying work,” Baizley offered. “Brigid had a job in a bank for a while but when she went to work in the community, it was more fulfilling.”

While people have this idea of nuns worshiping and praying, that was not the example that Rita McDonald showed her sisters.

“The world of women religious was not just about devotional rites but following the work that Jesus did, which means working with the poor,” Baizley said. “People don’t really think of a convent as a place where you become a social activist. But these sisters, living in a world that was all-female, were a part of the women’s movement.”

At the History Theatre, actor Sue Scott plays Jane. The others are depicted by well-known performers Wendy Lehr (Rita), Katherine Ferrand (Kate) and Peggy O’Connell (Brigid) in a production directed by veteran theater artist Barbra Berlovitz.

Don’t ask Jane, the youngest McDonald sister at 83, how it feels to watch an actor play her in rehearsal.

“It’s a little bit embarrassing in a way — you’re not used to that much focus,” she said. “It’s kind of like reliving some of those experiences.”

She’s glad that she’s not the one onstage, Jane added. “She does me better than I do.”

The play, which starts in 1955 — the year that Jane entered the order — is structured around four arrests. In their career of protests, the sisters went up against the Vietnam War, munitions manufacturers and the church, which excluded LGBT folks. In the play, they’re arrested while demonstrating for each of these causes — activism that redounded to their family, which is studded with military men.

The late K.J. McDonald, a Korean War veteran who became a state legislator and mayor representing Watertown, was their brother.

“He was very right-wing,” Baizley said. “But when I asked them about family gatherings at Thanksgiving, the sisters said something that’s instructive for the country. They never let an argument go over 24 hours. And they played a lot of cards. It was about their love for each other.”

The sisters were not always unrelenting peace activists, Jane explained. It was a gradual transformation that included trips to missile silos.

“I grew up under the idea about a just war,” Jane said. “I grew up believing and internalizing that war was a solution.”

But then the Vietnam War came along, and they became certain, through their readings and lecture attendance, that something wasn’t right.

“Educationally and geographically,” Jane said, “the tide turned in my own soul.”

Measuring success

If you’ve led a life of peace activism, how do you measure success?

“You don’t think in terms of results or impact because you don’t see it right away,” Jane said. “If you have to wait until you’re successful, you’d probably quit. We do it because it’s the right thing to do.”

The impact is more incremental, and part of a larger tide. “We’re just little ants going up the mountain,” Brigid said. “It’s a tough road.”

Brigid ticked off songs by Joan Baez and Bob Dylan. She called out the names of activist church leaders, including Archbishops Óscar Romero and Desmond Tutu, people who’ve affected the consciousness of the country and the world. They mentioned the growing political awareness of today’s young people.

Even so, Jane, at least, is not happy with where the country and the world are in terms of peace.

“That’s the sad part, isn’t it?” she said. “As far as U.S. policies, we’re still a warmongering country.”

The sisters can be unpopular voices in the wind. Whether on the bridge or talking with a reporter, they’re never shy about expressing their opinions. Brigid mentioned the near-paralysis of Venezuelan politics, wondering aloud if America simply covets the resources of the nation with the world’s biggest oil reserves.

But they are willing to pay whatever price for their moral rectitude, even in their ninth and 10th decades of life.

“The worst thing is when you have to go to jail,” Brigid said. “We’ve been arrested so many times. They call us trespassers but our drones and bombs are trespassing the whole world. The warmakers are the ones who should be arrested.”

Even if things haven’t changed that much, the sisters at least witnessed small graces as they were carted off.

“The best experiences we’ve had include some cops who wanted to protect us,” Jane said. “One great policeman wanted his picture taken with all the nuns to send to his mother in New York because she wouldn’t believe that he was arresting nuns.”

@rohanpreston