A municipal ballot proposal to divest from Israel went before a popular vote for the first time on Tuesday - and pulled off a decisive victory.

Question 3 won more than 55% of the vote in unofficial election results in the Boston suburb of Somerville, Massachusetts, as the Israel-divestment movement saw the elevation of its most well-known proponent in politics - Zohran Mamdani - to mayor of New York City.

Local pro-Palestinian activists claimed victory, with Somerville for Palestine - the group that gathered the signatures required to put the non-binding resolution on the ballot - posting a celebratory Instagram video alongside the Boston chapter of anti-Zionist group Jewish Voice for Peace.

However, as they were celebrating, the mayoral candidate best poised to enact the proposal in Somerville conceded his race to a rival who signaled he was far less likely to do so. Willie Burnley Jr., a democratic socialist who had endorsed Question 3, lost to fellow at-large city council member Jake Wilson, who did not.

A handful of other American cities have previously adopted Israel divestment proposals brought by their city councils. One of those is Portland, Maine, whose mayor publicly regretted backing divestment after hearing from local Jewish groups. An attempt last year to place a similar referendum on a Pittsburgh ballot failed after legal challenges to the signatures. Similar attempts to challenge the Somerville measure failed.

Home to Tufts University and several Jewish congregations, the four-square-mile Somerville has a population of around 82,000. Residents voted on whether its mayor should “engage in business that sustains Israel’s apartheid, genocide and illegal occupation of Palestine.” The local teachers union endorsed the measure.

Jewish groups opposed the measure, including the newly formed group Somerville United Against Discrimination, which ran TV ads against it. Brian Sokol, a Jewish IT manager and writer based in Somerville, implored his neighbors on Facebook to reject the measure - citing friends of his who were killed by a Hamas suicide bomber in Israel in 1996.

“I am not equating those in Somerville urging a Yes vote with violent extremists or terrorists,” he wrote. “But passing this ballot measure would unintentionally land Somerville on the wrong side of the deeper ideological rift.”

On the other side, a group of 84 local pro-Palestinian Jews endorsed the measure in an op-ed in the Tufts student newspaper. Celebrating the recent ceasefire in Israel and Gaza but saying that Israel has continued to commit atrocities in the region, the authors pointed to local contracts with two companies, Hewlett-Packard and Lockheed Martin, that total over $2 million.

Somerville became a flashpoint in the fight over campus pro-Palestinian activism earlier this year when a Tufts graduate student, Rümeysa Öztürk, was seized by ICE agents and put into deportation proceedings for writing an op-ed in the student paper urging divestment from Israel. A judge freed Öztürk while her deportation case remains ongoing.