In a crowded, diverse mayoral field, where does Marty Walsh’s base go?

In 2017, Martin J. Walsh kicked off his reelection campaign outside Florian Hall in Dorchester.JohnTlumacki

Martin J. Walsh’s ascension from City Hall to US labor secretary not only triggered a crowded scramble in this year’s mayor’s race but also raised the question of which candidate might inherit the voter base that powered the Dorchester Democrat’s victories.

While dozens of labor groups — Teamsters, painters, pipefitters — endorsed Walsh when he was running for mayor, providing his campaign with an army of volunteers, their support appears to be fracturing in this election. That dynamic is contributing to a race in which no clear front-runner has emerged with less than five months to go until the contest’s September preliminary.

Among the reasons: For one, no current candidate has the union bona fides that helped catapult Walsh to city executive, making local union support more likely to splinter in the absence of a candidate so uniquely connected to the labor movement.

Additionally, each election has its own dynamic, and this year’s race will likely be historic, as the city’s voters are expected to elect a Boston mayor who is not a white man for the first time, thanks to a diverse field of candidates.

James Rooney, president and chief executive officer of the Greater Boston Chamber of Commerce, is among those who expect Walsh’s political support to “go in a bunch of different directions.” Walsh’s base, he said, included unions, Walsh’s home neighborhood of Dorchester, which is Boston’s largest, and the city’s 18,000-strong municipal workforce.

“No one can galvanize the labor unions the way he did; they just don’t have the same background,” he said, nodding toward Walsh’s extensive labor experience. “I don’t think the Marty Walsh labor vote is going to move together.”

Eldin L. Villafañe, a government relations strategist at Barrales Public Affairs, said, “The job is on every candidate to go after a diverse base that Marty Walsh has cultivated over the years.”

“The business community, Black and brown communities, the LGBTQ community, and everywhere in between,” he said. “The question is what the contenders are going to do to reach that base? That’s their job, they’re going to have to work hard for it.”

There are six major declared candidates in the mayoral field: City Councilors Andrea Campbell, Annissa Essaibi George, and Michelle Wu; Acting Mayor Kim Janey, who was city council president before Walsh left City Hall; Walsh’s former economic development chief John Barros; and state Representative Jon Santiago.

Some have already attracted union support. Wu, an at-large councilor from Roslindale, appears to have the most labor support in the race to date. The Teamsters Local 25, which represents 12,000 workers, has endorsed her. So have OPEIU Local 453, which represents office and clerical workers at the MBTA, the Alliance of Unions at the MBTA, and the president of the Association of Flight Attendants-CWA.

The Massachusetts Nurses Association endorsed Essaibi George. Just this week, UNITE HERE Local 26, which represents 12,000 hotel and food workers, and has in the past been influential at City Hall, announced it is backing Janey.

Dorchester-based Laborers Local 223, one of the city’s biggest unions, endorsed Santiago. That local, which Walsh once led, represents 1,700 building trade workers. Santiago also snagged the endorsement of the National Association of Government Employees.

While Walsh enjoyed broad labor support in the 2013 race, Steven A. Tolman, president of the Massachusetts AFL-CIO, said recently, “You don’t know what can happen” this time around.

“Marty was one of us,” said Tolman.

When Martin J. Walsh faced off against challenger Tito Jackson in 2017, the city’s firefighters and police patrolmen unions endorsed the incumbent. Such city unions have yet to endorse in this election cycle.Jim Davis/Globe Staff

Walsh was 21 years old when he became a member of Local 223 in Boston, which his father had joined in the 1950s after emigrating from Ireland and his uncle later led. Walsh, a state representative for 16 years, went on to also serve as president of the union, then was the head of the Building and Construction Trades Council.

Plum endorsements remain. The Greater Boston Labor Council, a federation of scores of unions in the area, is among them. The council backed Walsh in 2013. The Boston Teachers Union endorsed Walsh in that race as well, while the American Federation of Teachers dropped $480,000 on Walsh advertising through a political action committee. When Walsh, as mayor, faced off against challenger Tito Jackson four years later, the city’s firefighters and police patrolmen unions endorsed the incumbent. Such city unions — BTU, the firefighters, and patrolmen — have yet to endorse in this election cycle.

When they do weigh in, their backing can help deliver votes. There are 1,138 union police officers who live in the city, 1,033 firefighters, and 2,607 union teachers, according to city data.

“There’s no one candidate that will appeal to unions,” said Sam Tyler, former head of the Boston Municipal Research Bureau. “I think they’ll be providing support to a number of candidates just to hedge their bets.”

The preliminary election is scheduled for Sept. 14. That contest will narrow the field to two, who will face off in the Nov. 2 general election.

Walsh has already said he won’t be making an endorsement in the race, stating that it wouldn’t be right. His political reach can nonetheless be seen all over the field.

Walsh was the boss of one candidate, Barros, and grew up on the same street as another, Essaibi George. As mayor, he at times jousted with some of the councilors who are running, including Campbell, Wu, and Janey, who still technically retains her seat on that body even as she serves as acting mayor. Some candidates will undoubtedly seek to boost their campaigns by running explicitly against Walsh policies.

In 2013, during his initial mayoral run, Walsh scored the backing of Joyce Linehan, a well-known, progressive Dorchester activist; the endorsement was seen as something that set Walsh apart from other union-backed pols. One local journalist once said that Linehan presides over “the most famous living room in Massachusetts politics.”

Linehan would go on to become Walsh’s policy chief. She is now a senior adviser to Barros’s campaign. Barros has the highest number of campaign workers, organizers, and advisers who have previously worked for Walsh in some capacity: seven — eight if you include the candidate. That group includes Conan Harris, who served in multiple roles in the Walsh administration and is married to Representative Ayanna Pressley of Boston.

Santiago’s campaign has three people who have previously worked for Walsh; Wu has two who served the city during the Walsh administration; Campbell has none. Janey’s campaign has a pair of consultants who volunteered pro bono for part of Walsh’s 2014 run.

There are multiple Walsh connections to the campaign of Essaibi George. Her campaign manager, Cam Charbonnier, was a Dorchester field organizer for Walsh and also served in other roles under the former mayor. Her communications director, Nicole Caravella, was a press secretary for Walsh for a time. Additionally, Essaibi George is utilizing a fund-raising consulting firm, LB Strategies, which the Globe reported in 2019 employed Walsh’s longtime partner, Lorrie Higgins. In the past, Walsh has used that firm for some campaign operations, including mailings, in addition to scheduling and managing his fund-raisers. LB Strategies did not respond to recent inquiries about whether Higgins still worked there.

Tim Sullivan, a former head of intergovernmental affairs for Walsh, is also doing some consulting for the Essaibi George campaign.

Milton J. Valencia and Timothy Logan of Globe Staff contributed to this report.