Incumbent Mike Thompson leads the June 2, 2026, top-two primary for California's 4th Congressional District after redistricting shifted the seat's boundaries, facing a notable intra-party challenge from Eric Jones alongside multiple Republican candidates. Thompson, a longtime moderate Democrat, benefits from established fundraising and name recognition in the North Bay and Central Valley areas, while Jones, a businessman and nonprofit executive, has drawn support from progressive groups seeking to energize younger voters. Early vote tallies indicate Thompson and Jones as the top two finishers advancing to the November general regardless of party, with Republicans trailing in aggregate. The race reflects California's jungle primary rules and broader midterm dynamics, where official certification timelines and any remaining ballot processing could finalize the exact order.