Incumbent Mike Thompson faces his most notable Democratic primary challenge in years from Eric Jones in California's June 2 top-two primary for the 4th Congressional District. Recent redistricting under Proposition 50 has incorporated new voters in Northern California areas including Napa and Sonoma counties plus Sacramento suburbs, altering the electorate from prior cycles. Jones, a younger entrepreneur with strong fundraising and endorsements from youth-focused groups, has positioned his campaign around mobilizing newer voters and criticizing establishment approaches. Thompson, a longtime moderate Blue Dog Democrat, benefits from name recognition and institutional support but must consolidate support in the altered district. Multiple Republican candidates and an independent also appear on the ballot, though the contest centers on which two Democrats advance to the general election in the solidly Democratic-leaning seat.