OAKLAND — Rep. Ro Khanna on Monday announced his endorsement of U.S. Sen. Alex Padilla, ending speculation that the progressive Silicon Valley Democrat would mount an intraparty challenge to Padilla next year.

Padilla (D-Calif.) this year became the first Latino to serve as a senator from California when he was appointed by Gov. Gavin Newsom to fill the seat vacated by Kamala Harris when she became vice president. That incumbency advantage in a Democratic state makes Padilla a heavy favorite to win in 2022, but Khanna had yet to endorse him until Monday, the last of California's 42 House Democrats to do so.

In April, Khanna said in a POLITICO interview that he was considering a U.S. Senate run, noting his increasingly active group of supporters in the Asian and Pacific Islander communities. He has a growing national profile as a progressive leader and prodigious fundraiser after he served as national director of Sen. Bernie Sanders’ presidential campaign.

“People don't support the safe incumbents in a seat … if they [don’t] believe that you're having a big impact," he said.

But Khanna's support for the sitting senator has ended a major threat to Padilla from the left.

"Senator Padilla has proven himself to be a progressive fighter in the Senate as an active supporter of the For the People Act, Medicare for All, and the Green New Deal," he said in a statement.

He added that "both Senator Padilla and I are proud sons of immigrants who came to the U.S. with dreams of a brighter future. I support Senator Padilla's mission to defend that dream for California's working families and I am proud to endorse his campaign for Senate in 2022."

Khanna has cited Padilla's moves to appeal to progressive voters, including backing the $15 minimum wage and calling to eliminate the Senate filibuster — a move cited by many as mandatory to pass a voting rights bill.

Padilla, who was previously a state senator and California secretary of state, will face his first election next year for U.S. Senate. In addition to getting Khanna's support, Padilla has a roster of powerhouse Democratic endorsements led by House Speaker Nancy Pelosi and Reps. Adam Schiff and Katie Porter. Padilla is also backed by the Democratic Senatorial Campaign Committee and Senate Majority Leader Chuck Schumer, as well as California's entire Democratic House delegation now — thanks to Khanna's endorsement.

“Ro Khanna is a next generation leader for California and the nation and I’m honored to have his support,” Padilla said in a statement Monday, vowing that he would work together with the congressman on various goals from Covid-19 recovery to "quality health care for all."