Incumbent Democrat Mike Thompson and challenger Eric Jones, both Democrats, advanced from California's June 2 top-two primary to face each other in the November 3 general election for the 4th congressional district. The district's partisan lean, rated solid or safe Democratic by Cook Political Report, Inside Elections, Sabato's Crystal Ball, and Decision Desk HQ, combined with voter registration favoring Democrats by a wide margin, underpins trader consensus for a Democratic outcome. Redistricting via Proposition 50 altered boundaries but preserved the district's overall Democratic tilt. A Republican victory would require an unprecedented reversal in this environment, such as a late candidate withdrawal or unforeseen development altering the November ballot.