On January 26, Adam Schiff announced for the U.S. Senate in 2024 in California. He is a member of the U.S. House. Another Democratic member of the U.S. House, Katie Porter, had already announced. And it is expected that two other Democratic members of the House, Barbara Lee and Ro Khanna, will announce.

This opens the possibility that in the 2024 top-two primary, if there are two fairly evenly-matched Republicans running for U.S. Senate, the two Republicans might conceivably place first and second, leaving Democrats with no candidate for U.S. Senate in November. California does not permit write-ins in the general election for congressional elections. Leaving the voters will no choice but to elect a Republican to the Senate seat would doom the top-two system in California.