Welp, one likely candidate in next year's race for California's soon-to-open-up Senate seat has taken himself out of the running, and that's South Bay Congressman Ro Khanna.

Khanna, who had widely been seen as a likely fourth candidate to announce his intention to seek the seat being vacated by a retiring Dianne Feinstein, said on Sunday that he was endorsing fellow Bay Area Rep. Barbara Lee — effectively taking himself out of the running.

The announcement came on CNN's "State of the Union" with Jake Tapper, and Khanna said that the best thing was "for me to serve as a progressive is in the House of Representatives." He added, "I’m honored to be co-chairing Barbara Lee’s campaign for the Senate and endorsing her today. We need a strong antiwar senator, and she will play that role."

As Politico notes, Khanna's move avoids "a further progressive split" on the ticket, with SoCal Rep. Katie Porter already having announced her candidacy. Rep. Adam Schiff is also running, and he was rewarded for his loyalty with an endorsement from Speaker Emerita Nancy Pelosi last month.

Democratic consultant Rose Kapolczynski tells Politico that Khanna likely read the tea leaves and didn't want to bolster Schiff's candidacy by taking more votes away from either Porter or Lee. "While Schiff is a progressive by most measures, progressive activists have been backing Porter or Lee," Kapolczynski says.

Khanna made clear that part of his calculus had to do with representation, and the longstanding fact that Black women have been sorely underrepresented in the Senate. Vice President Kamala Harris left the Senate as only the second Black woman ever to serve in the chamber, and currently there are none.

"Frankly, Jake, representation matters," Khanna said, per the New York Times. "We don’t have a single African American woman in the United States Senate. She would fill that role. [Lee will] be the only candidate from Northern California and she’s going to, I think, consolidate a lot of progressives. The other two are formidable candidates, but I think Barbara Lee is going to be very, very strong."

In a statement Sunday, Khanna said, "I am excited and proud to endorse my good friend Barbara Lee for U.S. Senate. Barbara is the progressive leader Californians need right now, and her solid record as one of Congress' most outspoken champions of justice speaks for itself."

And, as NBC Bay Area reports, Lee responded with her own statement, saying, "In the Senate, I promise to always stand up for our progressive values and be a voice for the voiceless, so we all have a seat at the table and, together, can deliver real change.  I've been doing this my entire career and I'll keep doing it in the Senate."

Lee made a name for herself in the House of Representatives in her first few years on the job, becoming the only member of Congress to vote against the Authorization for Use of Military Force (AUMF) on September 14th, 2001, which sent the first U.S. troops into Afghanistan in a war that only ended last year — and which many regard as a failure.

Previously: Now Barbara Lee Is Running For Feinstein’s Senate Seat, Setting Up a Democratic Party Royal Rumble