Incumbent Democrat Mike Thompson seeks his 15th term in California's 4th Congressional District primary on June 2, facing a well-funded primary challenger in Eric Jones amid redistricting that added nearly half new rural territory through Proposition 50. Multiple Republicans, including Ray Riehle, Sharon Brown, and Mandy Ghusar, compete for the second advance spot under the state's top-two system. Thompson highlights his Ways and Means Committee role, farm background, and measured tariff approach, while Jones emphasizes progressive priorities such as expanded Medicare access, child care support, and family farm grants. Fundraising and local endorsements have concentrated attention on the two Democrats, with forecasters rating the seat Solid Democratic for the general election.