Incumbent Rep. Mike Thompson (D) dominates the June 2 top-two primary for California's 4th Congressional District, bolstered by over $2.5 million cash on hand, Democratic Party of California endorsement, and recent backing from the Sacramento Bee editorial board amid ballots mailing this week for early voting starting May 4. Progressive challenger Eric Jones (D), with $1.4 million cash raised largely from Silicon Valley donors rejecting corporate PACs, poses the main Democratic threat but trails in party support following earlier backlash. A fragmented Republican field of six candidates, including small-business owner Raymond Riehle, lacks competitive fundraising, likely ensuring the top two advance as Democrats in this D+17 leaning district reshaped by 2025's Proposition 50 redistricting. No recent polls available; outcome hinges on turnout in the final weeks before polls close June 2.