Incumbent Mark DeSaulnier holds a commanding position in California's 10th congressional district due to its strong Democratic lean in Contra Costa and Alameda counties, where he has represented the seat since 2014. In the June 2026 top-two primary, DeSaulnier secured nearly 60 percent of the vote while Republican Jeff Frese advanced with under 13 percent amid a fragmented GOP field. Forecasters including the Cook Political Report and Sabato's Crystal Ball rate the race as Solid or Safe Democratic, reflecting the incumbent's established fundraising advantage and the absence of competitive opposition. A realistic shift would require an unexpected national political realignment or major district-specific development before the November 3 general election.