Joe Biden has won the Democratic primary in Michigan – but a concerted effort by anti-war activists to vote “uncommitted” in the race could overshadow his win.

The US president faced no real primary challenger in the contest. But a campaign that formed just weeks before the primary to vote “uncommitted” in protest of his continued support for Israel’s war in Gaza signaled the fury and betrayal some Arab American and younger voters in the state feel for Biden.

The group pushing for voters to choose “uncommitted” – called Listen to Michigan – set the goal of 10,000 uncommitted votes in the primary, roughly the same margin that Biden won Michigan by in 2020. With only 31% of the votes tallied, “uncommitted” had received more than 40,000 votes. For context, when the then president, Barack Obama, ran uncontested in the 2012 race, about 21,000 voted “uncommitted” against him in that state’s primary, with about 194,000 voting in total.

As results came in after polls closed at 8pm, members of the Listen to Michigan campaign gathered at a banquet hall in Dearborn. Attendees embraced and celebrated the turnout so far for the “uncommitted” campaign, many wearing the black and white keffiyeh. Before handing the microphone off to a series of speakers for the campaign, Abbas Alawieh, a Listen to Michigan spokesperson, held a moment’s silence “for every human life that has been taken from us too soon using US taxpayer funds and bombs”.

Organizers with the “uncommitted” effort have called the night’s results a victory for their campaign to demonstrate opposition in the critical swing state to Biden’s unwavering support for Israel’s military operations in Gaza.

“Thank you to our local and national progressive organizations and our voters of conscience, who used our democratic process to vote against war, genocide and the destruction of a people and a land,” said Layla Elabed, who launched the campaign in early February.

The former congressman Andy Levin, an early and prominent local supporter of the push to vote “uncommitted”, called the movement “a child of necessity” and said the turnout so far was “a huge victory”.

“There is no hope for security and peace for the Jewish people without security and peace and freedom and justice for the Palestinian people,” said Levin, to cheers.

The Listen to Michigan campaign was intended as a warning for Biden to revise his so far unwavering support for Israel’s campaign in Gaza, which has killed nearly 30,000 Palestinians, ahead of the general election. But this campaign is especially significant in Michigan given the state’s large Arab American population, a group that supported Biden strongly in 2020.

But it isn’t clear what share of “uncommitted” voters are prepared to abandon Biden in the general election this November, when he will most likely face Donald Trump – who is campaigning on a pledge to reinstate and expand his Muslim travel ban.

A day before the primary, Biden announced a ceasefire could come as soon as Monday – but both Hamas and Israeli officials denied that negotiations had progressed substantially.

In a statement on Tuesday night, Biden did not address the Listen to Michigan campaign or the growing tally of voters who cast their ballots as “uncommitted”, instead touting his record on labor and warning that Trump is “threatening to drag us even further into the past as he pursues revenge and retribution”.