Opposition to President Joe Biden’s strong support of Israel’s “war” against Hamas faces a fresh test on Tuesday in Wisconsin where pop-up groups on a shoestring budget are urging voters to mark themselves uncommitted in the state’s Democratic primary, Reuters reports.

For two weeks, 60 grassroots groups and organizers have advanced their cause with phone banks, mailers, banners, knocks on doors and “friend banks” where volunteers contact friends who then contact their friends.

Their goal is to get 20,682 voters to mark their ballots “uninstructed,” Wisconsin’s version of “uncommitted.” The number is significant. Biden, a Democrat, beat Republican Donald Trump by that number in the state in the 2020 presidential election.

It remains unclear whether these uncommitted voters will abandon Biden and cost him the White House.