Milton State Sen. William Driscoll spent Wednesday, Sept. 9, at Boston City Hall as a poll watcher in a hand recount that could decide one of the tightest state Senate races in Massachusetts history.

Driscoll, who represents the Norfolk, Plymouth and Bristol Senatorial district, was one of 11 sitting senators who showed up to back incumbent Sen. William Brownsberger, the Senate's president pro tempore. Most served as official poll watchers for Brownsberger's campaign, Commonwealth Beacon reported, citing State House News Service.

The display matters to Milton residents because it signals where their senator stands in a fight that has split Beacon Hill. Boston Mayor Michelle Wu backed challenger Daniel Lander, a former senior Wu aide, after Brownsberger helped kill Wu's plan to shift more of Boston's property tax burden onto commercial real estate. Wu also targeted Sen. Nick Collins over the same vote. Collins easily won reelection.

Certified results entering the recount showed Brownsberger leading Lander by 34 votes, a margin of 50.1% to 49.9%. Roughly 24,000 ballots were cast across the Suffolk and Middlesex District, which covers Boston, Belmont, Cambridge and Watertown, according to the Boston Herald.

The margin swung during Wednesday's count. By one early unofficial tally, Lander pulled ahead by three votes. Later counts put Brownsberger back in front by just over two dozen, Commonwealth Beacon reported.

Some senators arrived in casual clothes and drank the Dunkin' coffee provided for volunteers. Brownsberger paced the floor in his suit. Sen. Michael Rodrigues of Westport, chair of the Senate Ways and Means Committee, told State House News Service he left home at 6:30 a.m. to reach City Hall.

"It's almost a caucus in the Senate here as volunteers because my opponent doesn't have a grassroots operation," Lander told State House News Service from the recount floor.

Staff members for Senate President Karen Spilka also attended. Spilka's advisor Eileen O'Connor issued a statement defending the senators' presence, saying Brownsberger had earned his colleagues' respect through his work in the Senate, the Herald reported.

Boston completed its recount Wednesday, certifying results at 5:42 p.m. that upheld Lander's 1,762-vote margin in the city. Watertown also finished. Belmont and Cambridge were scheduled to complete their counts on Thursday, Sept. 10. Secretary of State William Galvin set a deadline of 5 p.m. Friday, Sept. 11, for all four municipalities to certify results.