Former Rep. Cori Bush is mounting a challenge to unseat incumbent Rep. Wesley Bell in Missouri's 1st Congressional District primary on Tuesday, intensifying a schism within the Democratic Party. The race highlights the ongoing tensions between progressive and establishment factions of the party, particularly concerning U.S. policy toward Israel.

Bush, a member of the Democratic Socialists of America (DSA), has made Bell's support for Israel a central theme of her campaign. In a recent advertisement, Bush accused Bell of prioritizing a trip to Israel funded by donors associated with the American Israel Public Affairs Committee (AIPAC) over addressing the recovery needs of St. Louis following a devastating tornado in May 2025. The ad stated that Bell "jetting off to Israel with AIPAC" occurred as the city faced "$1.6 billion in damages and took several lives."

Bush also claimed on social media that Bell, a former Republican campaign manager, is "bought and paid for by AIPAC" and that her supporters will return her to Washington "with no corporate cash or AIPAC-funded trips."

Bell's campaign defended his record, pointing to his efforts to secure disaster relief funds for St. Louis. A campaign spokesperson shared a recent debate response from Bell, in which he detailed his work with a bipartisan congressional delegation to secure over $200 million in FEMA disaster relief. Bell's campaign also shared an ad featuring a constituent who called Bush's criticisms "just politics" and defended Bell's tornado response.

The conflict over U.S.-Israel relations has become a significant fault line within the Democratic Party since the Hamas attacks on Oct. 7, 2023. Bush, a vocal critic of Israel's military operations in Gaza, previously voted against emergency funding for the nation and accused its government of genocide. Bell, by contrast, is described as a more pragmatic Democrat who previously served as a county prosecutor.

Bush narrowly lost her seat to Bell in the 2024 general election, attributing her defeat in part to external funding from pro-Israel groups, including those affiliated with AIPAC, that supported Bell. The current rematch occurs as candidates linked to the DSA are increasingly challenging established Democrats in primaries across the country, with some notable successes in New York and Colorado.