When Marty Walsh was one of a dozen candidates running for mayor, his background as a labor leader was viewed as a hindrance as critics questioned whether, as the city’s chief executive, he could handle negotiations with the city’s unions.

But his time in the building trades and his tenure as a Dorchester state representative, were, in fact, two of his biggest assets. During his time in office at City Hall, city finances remained stable, even during the pandemic.

For much more Boston-based political news, see The Lit Drop, powered by DotNews.com and the Dorchester Reporter.

During the 2013 race for mayor, union ground troops spread out across the city, joining progressive activists to back Walsh. One rival, driving around the city the day of the September preliminary election, marveled at the number of red-shirted Walsh supporters out on the streets. They pulled in voters and put him in first place both in the preliminary and the final, with additional help from high spending outside groups aligned with labor unions.

Seven years later, the unions are split and scattered in their endorsements as Walsh’s departure for Joe Biden’s cabinet has led to six major candidates jumping into the race to succeed him: Acting Mayor Kim Janey, state Rep. Jon Santiago, former City Hall economic development chief John Barros and City Councillors Michelle Wu, Annissa Essaibi George, and Andrea Campbell.

“Back in 2013, and I’ll speak for unions in general, it was pretty easy to see the path,” says Joe Byrne, the executive secretary treasurer of the North Atlantic States Regional Council of Carpenters, who hasn’t endorsed yet. “Today, it’s a wide-open race.”

Endorsements, not just from unions, come in varying sizes and weights during every election cycle, ranging from ones that provide ground troops and cash to the random people on Facebook or Twitter who may not even live in the city but feel compelled to pop off before getting on with their days.

The heavyweight unions that haven’t announced whom they’re backing include the Boston Teachers Union, health care workers of SEIU 1199, and property service workers of SEIU 32BJ. Unions that have settled on a candidate include Teamsters Local 25, which is backing Wu; the Boston Emergency Medical Services union, and Firefighters Local 718 which have endorsed Essaibi George; and Laborers Local 223, the union led by Walsh’s cousin, also named Marty Walsh, which has given its nod to Santiago.

Some may wait to endorse until after the Sept. 14 preliminary, when the field will be down to two candidates. But 32BJ is aiming for an endorsement in July.

Roxana Rivera, 32BJ’s vice president and local leader of the union, said her members were among the hardest hit during the pandemic, which caused a shutdown in economic activity across the globe.

Her union represents 20,000 workers in Massachusetts, many of them immigrants and people of color. Some 6,000 members live within the city of Boston, and another 5,000 work in the city but live in nearby Chelsea, Lynn, Everett, and Revere. They work inside commercial office buildings, bio-techs, higher education, and the airport. “They had to show up to work while other people could work at home,” Rivera said.

The historic nature of the race, in particular, the number of women of color running, matters to her union members, Rivera added. So do candidates’ personal narratives and their stances on improving working conditions within the city.

“We want to be able to make an impact in this September primary for any candidate that we endorse,” Rivera said.

IBEW Local 103, the Dorchester-based electrical workers union, also hasn’t made an endorsement, though Louis Antonellis, the union’s business manager, made a $500 donation to Janey in May, according to public campaign finance filings. He did not respond to a request for comment. (He last gave to Walsh — $1,000 in December — before Walsh took the job of labor secretary and handed the reins to Janey.)

Steve Tolman, the head of the Massachusetts AFL-CIO and a Boston resident, took note, like Rivera, of the quality of the six-person field.

“Having been a big supporter of Marty Walsh, I think we do have a talented bunch who are seeking the job,” he said. “I haven’t made my mind up.”

Among endorsements from elected officials, no one looms larger than Ayanna Pressley, the congresswoman and former city councillor at-large. The Dorchester Democrat is now a national figure, along with New York Congresswoman Alexandria Ocasio-Cortez and other members of their “squad.” Pressley hasn’t made an endorsement, and it’s unclear when one could arrive.

Close campaign watchers are also keeping an eye out for endorsements like the Boston Globe’s. In 2013, the newspaper made the strange move to endorse two candidates when voters had just one choice in the preliminary: The editorial board, which is separate from the newsroom, endorsed Barros and City Councillor At-Large John Connolly days before the preliminary. The board, which prefers to leave its editorials unsigned, endorsed Connolly again in the final election.