Mike Thompson holds the leading position in the CA-04 House race at 71% implied probability due to his long incumbency since 1999, strong Democratic Party endorsements, and the district’s Solid Democratic rating from forecasters despite redistricting that added Republican-leaning areas. Eric Jones, at 26.5%, advanced from the June 2026 top-two primary as the sole challenger after narrowly outpacing the top Republican, positioning the November 3 general election as an intra-party contest focused on affordability and generational turnover. Recent developments include Jones securing a cross-party endorsement from primary opponent Raymond Riehle to mobilize independents and Republicans, alongside Jones’ repeated debate challenges across the nine-county district. Other listed candidates remain at 50% as they did not advance beyond the primary.