Incumbent Rep. Wesley Bell (D) defeated four other candidates in the Democratic primary for Missouri's 1st Congressional District on Aug. 4, 2026. Bell and Cori Bush (D) led in noteworthy endorsements and fundraising.
At the time of the election, this primary was one of five in the 2026 election cycle in which a former member of the U.S. House of Representatives ran against an incumbent member. Bush represented Missouri's 1st Congressional District from 2019 to 2025. In 2024, Bell defeated Bush 51.1% to 45.6% in a field of four candidates.
During the 2024 primary, the American Israel Public Affairs Committee's (AIPAC) affiliate, the United Democracy Project (UDP), spent approximately $8.5 million either against Bush or in support of Bell. The Cook Political Report'sMatthew Klein wrote that "As the Democratic electorate grows increasingly angry over the war in Gaza and AIPAC's meddling in primaries across the country, Bush is counting on an anti-Israel backlash to put her over the top." As of July 24, 2026, the UDP had spent $2.5 million in the 2026 primary, and AIPAC endorsed Bell.
