There are so many Democrats running for Congress in some districts that they could split the votes in the June 5 primary and send two Republicans to the November election, thanks to California’s top-two primary system. Democrats need 24 seats to reclaim the majority in the U.S. House — and are putting money and attention toward 10 California contests. In other words, every race matters.

The volume of Democratic candidates is a particular problem in Issa’s 49th Congressional District in San Diego and south Orange County.