Mayor Michelle Wu on Monday endorsed Daniel Lander, her former aide who’s challenging veteran state Senator Will Brownsberger, taking what one expert called a “cutthroat” political move in her escalating fight with Beacon Hill leadership.
Brownsberger, a Belmont Democrat who represents parts of Boston, is the third-ranking Democrat in the state Senate and one of the key voices who nearly two years ago sounded the death knell for Wu’s plan to shift the city’s tax rates, a key legislative priority of the mayor’s, and voted against it again earlier this year.
Wu, in the matter of weeks, has inserted herself into two closely watched Senate primaries in Boston, pitting herself against foes, and fellow Democrats, at the State House. The mayor earlier this month endorsed Latoya Gayle over incumbent Nick Collins of South Boston, with whom she has fiercely, and publicly, clashed.
Her decision to weigh in on Lander’s challenge is not unexpected but still notable for other reasons.
The Suffolk and Middlesex district expands beyond Boston into Cambridge, Watertown, and Belmont, putting Wu’s political reach to the test in cities and a western Boston suburb where she’s never been on the ballot. Brownsberger also has the backing of Governor Maura Healey, who in endorsing him called him “instrumental” to getting a sweeping housing law over the finish line.
In a statement, Wu said she worked with Lander “to deliver for Boston families.”
“I know he’ll bring that same results-driven leadership to the State Senate,” Wu said. “Daniel never backs down from a fight and he knows how to get things done. I’m confident he’ll be a champion for affordable housing, better transit, and a stronger partnership between the state and our City.”
Lander, 35, trumpeted the high-profile endorsement just days after US Senator Elizabeth Warren also publicly backed his campaign.
“It shows this campaign has real legs,” he said.
Brownsberger said in an interview that he was not surprised by the endorsement, saying he felt that Wu was “behind [Lander] all along.”
He noted he has endorsements from other elected officials, including Attorney General Andrea Campbell, several state representatives, and several elected Cambridge city officials.
“Most other local officials are endorsing me because they know what a great partner I am,” Brownsberger said.
Wu’s endorsement is nevertheless an escalation for a mayor who personally is electorally safe — she rolled to reelection last fall — and is trying to shift the balance of power on Beacon Hill toward her policy priorities, said Erin O’Brien, a political science professor at UMass Boston.
Wu already helped install several allies on the City Council and aided political newcomer Allison Cartwright in topping City Councilor Erin Murphy for the oft-ignored role of clerk of the Supreme Judicial Court for Suffolk County two years ago.
But to now directly target sitting state senators, Wu is sending a message that “there may be electoral consequences” for those who don’t help her, O’Brien said.
“It’s more cutthroat than she’s been in the past,” she said.
Wu and Lander first met during Warren’s 2020 bid for president, Lander said. They bonded over a campaign trip together in New Orleans, where the rental car company provided them with a giant pickup truck to drive, embarrassing Lander, who said he knew he was working with a city councilor who’d later tout a “Green New Deal” for the city as mayor.
He later joined her mayoral campaign as an adviser in 2021, and Wu hired him into her administration as a policy aide, a role he left in January when he launched his Senate campaign.
In City Hall, Lander worked on policy to audit city-owned land that could be turned into housing, and helped establish the city’s “Family Days” program that opened the city’s museums and attractions to Boston students for free.
Lander also said he was a vocal supporter of Wu’s proposal to shift more of the city’s property tax burden onto commercial real estate to ease property tax spikes for homeowners.
Brownsberger has explained his views extensively in public blog posts on his website, where he details his viewpoints and the historical facts of how the city’s business-residential property tax split came to be and allows commenters to weigh in.
In his words, shifting property tax rates “is not an efficient way to deliver relief” to homeowners, and raising commercial taxes could hamper the city’s effort to revitalize downtown, which is still recovering from the COVID-19 pandemic.
He has also argued that state lawmakers’ role is not simply to acquiesce to local leaders on issues that can have ramifications beyond those cities and towns.
“We are one Commonwealth, there are 351 cities and towns,” Brownsberger said at a candidate forum last week at Berklee College of Music. “It’s entirely appropriate that there should be statewide rules on things like taxes, transportation.
Samantha J. Gross can be reached at samantha.gross@globe.com. Follow her @samanthajgross.