California voters on Tuesday overwhelmingly approved Gov. Gavin Newsom’s measure that allowed the state to redraw its congressional map in favor of Democrats, pushing back against President Donald Trump’s effort to hold onto a Republican-controlled Congress by urging redistricting in Texas.

Tuesday capped off a whirlwind, hyper-partisan two-and-a-half-month campaign for one of the most expensive ballot measures in state history. Supporters poured more than $120 million into Newsom’s committee supporting the measure. Opponents raised just $44 million. Outside groups spent $27 million to try to sway the vote.

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Newsom declares victory

In a triumphant speech, Newsom proclaimed that Prop. 50’s victory was not just a win for California, but a win for the entire country. He called on leaders in other Democratic-held states — Illinois, Virginia, Maryland and New York — to “meet the moment” and redraw their congressional districts, too.

“Instead of agonizing over the state of our nation, we organized in an unprecedented way,” Newsom said. “Tonight, I’m proud. But I’m very mindful and sober of the moment we are living in. Donald Trump does not believe in fair and free elections, period and full stop.”

Prop. 50’s passage marked a significant victory for the governor, who took a political risk on the measure, calculating that it would give the state’s Democratic voters who are frustrated with the Trump administration a way to “fight back.”

Gov. Gavin Newsom speaks to the press, alongside his partner Jennifer Siebel Newsom, after Proposition 50 was passed by California voters, at the California Democratic Party headquarters in Sacramento on Nov. 4, 2025. Photo by Jungho Kim for CalMatters Though opponents criticized him for using the measure to burnish his national profile, Newsom was joined in his effort by numerous liberal groups, who argued that helping Democrats win the House could counter the administration’s aggressive immigration raids, cuts to social services and erosion of democratic norms.

Republicans vowed they will still challenge Democrats statewide, and said the election distracted from issues like the cost of living.

“Even under this new map, Republicans have clear opportunities to flip seats because Californians are fed up with Democrat chaos,” National Republican Congressional Committee chairman Richard Hudson said in a statement.

What this means for incumbent Republicans

Five GOP congressmembers now face steep odds to re-election and are more likely to lose their seats after next year’s midterms:

• Rocklin Rep. Kevin Kiley reaffirmed Tuesday night he’ll run for re-election despite his 3rd District becoming more liberal: “Politicians can change the lines on a map, but they can’t tell you how to vote.”
• Chico Rep. Doug LaMalfa, whose 1st District in the vast rural northeast corner of California, will lose several conservative counties and take in liberal Santa Rosa, has also said he will run again.
• Corona Rep. Ken Calvert will have to decide whether to run in a primary against a fellow Republican after his Riverside County district moves completely. He’ll instead be in the safe Republican 40th District held by Rep. Young Kim.
• Hanford Rep. David Valadao’s district in the southern Central Valley will become slightly more Democratic and stretch closer to Fresno. The race could still be competitive; the Republican has held onto his seat despite a Democratic registration advantage.
• Escondido Rep. Darrell Issa’s eastern San Diego County district will lose conservative pockets and gain liberal voters in the Coachella Valley. He said Tuesday night that he’s “not quitting.”

An election worker puts two ballots in a curbside ballot drop box outside a vote center at the Huntington Beach Central Library in Huntington Beach on Nov. 4, 2025. Photo by Jules Hotz for CalMatters

What this means for Democrats

Five Democratic House incumbents have seen their districts grow safer under Prop. 50:

• Rep. Josh Harder, a Stockton Democrat, was swept into Congress during the 2018 Democratic wave and he has held onto his Stockton-based seat despite being a perpetual Republican target.
• Rep. Adam Gray of Turlock had the closest 2024 House race in the country. With more Democratic voters from Stockton, it will be much easier for him to hold the seat next year.
• Rep. George Whitesides of Santa Clarita represents northern Los Angeles suburbs in the 27th District that have grown gradually more liberal. His new seat brings in more Democratic voters from the San Fernando Valley.
• Rep. Derek Tran of Cypress should have an easier time defending his seat in the heavily Asian 45th District, which straddles Orange and Los Angeles counties.
• Rep. Dave Min of Costa Mesa won his 47th District seat by fewer than three percentage points last November. The new map shifts his district away from Huntington Beach and Newport Beach.

While numerous Democrats have been running assuming the new maps would apply, several are poised to switch districts now:

• Rep. Ami Bera in Sacramento County, will shift from the 6th District to challenge Kiley in the 3rd District.
• In turn, Dr. Richard Pan, a prominent former state senator who had already declared a challenge against Kiley, said he will now run in the 6th District.
• Two candidates challenging Calvert in his current district — Brandon Riker and Anuj Dixit — have said they will instead challenge Issa in the newly drawn 48th District.

Trump threatens ‘legal and criminal’ review

Trump threatened Tuesday to challenge California’s mail-in ballot results, claiming without evidence that it was fraudulently conducted — even before any results were in.

The president said there would be “very serious legal and criminal review” of the state’s use of universal mail ballots. White House spokesperson Karoline Leavitt later said Trump was working on an executive order to strengthen elections and assure there isn’t “blatant fraud” in California’s universal mail-in ballots.

About 7 million Californians had already voted by Election Day, 4.6 million of whom put their ballots in the mail. Another 2.3 million put a ballot they received in the mail at a ballot drop-off box or at an elections office. For more than a decade, the majority of voters in California elections have participated by mail. Voter fraud is extremely rare, and studies have found no evidence that voting by mail increases fraud.

This article was originally published on CalMatters and was republished under the Creative Commons Attribution-NonCommercial-NoDerivatives license.