Senator Nick Collins at the annual St. Patrick's Day South Boston breakfast in 2025 By Margot Murphy (Massachusetts Governor’s Press Office)

SOUTH BOSTON STATE Sen. Nick Collins fended off a challenge from his left flank on Tuesday night, but Belmont state Sen. Will Brownsberger’s fate was hanging by less than 100 votes by Wednesday morning. The two senators representing Boston fought for their political lives this election season against progressive challengers backed by Mayor Michelle Wu.

Despite Massachusetts’s notoriously uncompetitive elections, a series of progressive upstarts saw an opportunity up and down the ballot to try to boot incumbents. For the most part, they were unsuccessful.

Collins, first elected to the Senate in 2018, is set to head into another term representing the First Suffolk district after securing about 54 percent of the vote in a tight race against first-time candidate Latoya Gayle, an early education advocate from Dorchester.

Another first-time candidate, Daniel Lander, kept the Suffolk and Middlesex District race within an eyelash against 14-year incumbent Brownsberger. Unofficial results showed Brownsberger up by 61 votes with all precincts counted, with the possibility of a recount in the air.

Wu took the unusual step of publicly backing primary challengers against the two sitting state senators — a level of direct involvement in Beacon Hill races that can be a risky public bet for a Boston mayor and leave questions about the presumed independence of the candidates. Wu has said it isn’t personal. The senators, she argued, were voting “against the interests of their constituents.”

The vote that flipped the switch took place in January. The state Senate rejected Wu’s plan to temporarily shift more of Boston’s property tax burden onto commercial real estate, a move meant to soften a spike in bills for homeowners. Collins and Brownsberger led the opposition.

In the First Suffolk District — South Boston, Dorchester, the South End — Wu endorsed Gayle over four-term senator Collins.

“Average folks, people, don’t know what’s going on at the State House,” Gayle told WBUR while door-knocking, arguing voters were ready to ask for more than incumbency.

“Sometimes you have to dust off the cleats,” Collins told the Boston Globe in an interview Tuesday night. “Nobody owns a seat, and I think it’s made me a better senator. It’s tested my team and brought out the best in the district.”

Gayle conceded the race just after 10 p.m., according to the Dorchester Reporter. Of Collins’s remark that he is a better senator because of the contest, Gayle said, “I hope he means that.”

According to the unofficial vote breakdowns, South Boston locked in the final win. While the two candidates largely split the wards throughout the district, the South Boston senator carried his home neighborhood by over 2,000 votes, with his overall margin of victory just over 2,300 votes.

Collins dramatically outraised and outspent Gayle, with the incumbent senator and former state representative hauling in $415,000 and spending about $408,000 from January through August. Gayle, whose committee opened in December, raised about $73,000 and spent about $55,000 over a comparable eight-month span, but did not have an August filing with the Massachusetts Office of Campaign and Political Finance.

Boston-focused political action committees were also active in the race. Citizens for an Affordable Massachusetts and A Balanced and Better Boston, which has ties to former Mayor Marty Walsh, spent at least $95,700 supporting Collins. Gayle, meanwhile, drew support from the Wu-aligned Boston Leads PAC, which spent more than $80,000 between her and the other upstart with the mayor’s backing.

In the Suffolk and Middlesex District, spanning Belmont, Watertown, and parts of Boston and Cambridge, Wu endorsed her former City Hall aide Lander against Senate President pro tempore Brownsberger, a 14-year incumbent from Belmont.

“My track record has been a force for good in every session,” Brownsberger told the Charles River Regional Chamber of Commerce at a candidate debate.

Lander boasted the backing of progressives in and outside of the Bay State, including New York Mayor Zohran Mamdani, US Sen. Bernie Sanders, and US Sen. Elizabeth Warren, for whom Lander served as senior political adviser to her 2020 presidential campaign. US Rep. Katherine Clark, Gov. Maura Healey, Lt. Gov. Kim Driscoll, and Attorney General Andrea Campbell all endorsed Brownsberger.

Neither candidate has August filings with the state campaign finance office. Lander’s committee raised about $187,100 from December through the end of July and spent just $44,850. Brownsberger, who started the race already sitting on roughly $180,800, pulled in another $331,900 over the same eight months and spent about $277,100.

While the Collins seat was a test of Boston mayoral power entirely within Boston, Brownsberger represents one of the split districts where non-Boston electeds represent the capital city often chafing against Beacon Hill’s iron grip.

Based on the Associated Press’s vote data, Lander preserved narrow margins in Cambridge and Watertown while ending with a roughly 1,700-vote lead in Boston. But Belmont came out for its sitting senator, with the Middlesex town handing Brownsberger a lead of about 2,200 votes.

Collins and Brownsberger became the face of Wu’s frequent clashes with the state Senate, though the House has also waved away her efforts to change policy through proposals like a tax on high-value real estate sales and a swing at rent control.

On Beacon Hill, with a reputation for opacity and top-down leadership, swapping sitting senators for first-time progressives may have limited utility when it comes to vote count. But Tuesday sent the signal that local representatives perceived as unfriendly to the city’s goals should expect rockier roads in future primaries.

State Sen. Lydia Edwards, of East Boston, a Wu ally, told the Boston Globe earlier this year that she wondered if Wu’s endorsements constitute “normal politics” or “a division that can’t be mended.”

The tax vote cut the other way as well, with Wu endorsing Sen. Mike Rush, a moderate West Roxbury Democrat who proposed Wu’s bill as an amendment to legislation the Senate advanced. Rush faced his first primary challenge in almost two decades from progressive attorney Persis Yu, which is also sitting at a razor thin margin with Yu up by less than a percentage point.

No Republican has filed in either Boston district, so Collins and the ultimate victor in the Suffolk and Middlesex race will sail through the general election to fill the seats for the next term.

Jennifer Smith writes for CommonWealth Beacon and co-hosts its weekly podcast, The Codcast. Her areas of focus include housing, social issues, courts and the law, and politics and elections. A California...