All the major Prop. 50 changes explained

Proposition 50, the Democratic-backed ballot measure to temporarily redraw the state’s congressional maps, has scrambled California’s congressional playing field in more ways than you might think.

Yes, it’s given Democrats the opportunity to flip up to five Republican-held seats, said Erin Covey, House editor at the Cook Political Report. But it’s also made a handful of blue districts even safer. That, Covey said, puts Democrats in a position to beat Republicans — who set off the mid-decade redistricting fight — at their own game nationally.

“In terms of the national redistricting outlook, I think that California is basically putting Democrats in a position where they may be able to fight this to a draw or at least limit Republicans to only picking up maybe three or four seats through redistricting alone,” Covey said.

That’s despite the fact that far more GOP-led states have moved to redraw their maps ahead of 2026 than blue states. Texas, the first to redraw its maps at the behest of President Donald Trump, just saw its new districts blocked by a district court. It’s unclear whether that ruling will stand if the U.S. Supreme Court decides to weigh in.

“Seats are going to flip as a result of these new maps [but] a lot of these maps cancel each other out. And so we’re in kind of an interesting situation where it may not be quite as good for Republicans as they anticipated going into this,” she said. “Without California, that would not have been possible because of the sheer number of seats that the California map affects. It really was a significant achievement on the part of Democrats and could potentially make the difference in the majority next year.”

Here’s a look at the biggest shifts under Proposition 50 — with thanks to Covey and the number crunchers over at the Cook Political Report for many of the data points below.

Congressional District 1

The new North State district is seen as an easy pickup opportunities for Democrats.

District 1, currently held by Republican Doug LaMalfa, shifted west and now includes both Chico and Santa Rosa. Under the old map, Trump won the district by 25 points; under the new boundaries, he would have lost by 12. LaMalfa said he will run, but it’s going to be tough: State Senate President Mike McGuire, who has represented Sonoma County in the Legislature for 12 years, is in the race, along with Audrey Denney, an educator and consultant who unsuccessfully challenged LaMalfa twice.

Congressional District 3

District 3, represented by Republican Rep. Kevin Kiley, now includes more of Sacramento County and shifts from a Trump +3 to a district former Vice President Kamala Harris would have won by double digits.

Two Democrats have announced their intention to run: Rep. Ami Bera and Nevada County Supervisor Heidi Hall. The big question, Covey said, is what Kiley does.

“He could choose to stay in the Third, which of course would be very tough,” she said. “He could move to the Sixth District, which is also a seat that Harris would’ve won by eight points in 2024. … And then the third option for Kiley outside of retiring or running for something else entirely would be to run in the Fifth District, which is Tom McClintock’s seat.”

McClintock, a Republican, has been in Congress since 2009.

District 22

Aside from 2018, when Central Valley GOP Rep. David Valadao fell victim to a blue tidal wave that swept Democrats into control of Congress, the 22nd District has been a thorn in the side of Democrats.

Valadao has defied political gravity, winning over working-class Latino voters to hang on to a seat even when party registration favored Democrats. In 2024, he won by seven points to Trump’s six. But with the new Proposition 50 lines, the current 22nd would have favored Trump by less than two points.

Health care could be central here: six out of 10 residents are enrolled in Medi-Cal, the state’s Medicaid program.

“His biggest vulnerability going into this election is the impact that the Big Beautiful Bill has on health care, in particular Medicaid cuts,” Covey said. “The district has shifted to the right in recent years as a lot of the Hispanics in the Central Valley have become more and more open to voting for Trump.”

Whether that holds after Trump’s immigration crackdown, and amid affordability concerns, is unclear.

Several Democratic candidates are running, including Dr. Jasmeet Bains, a moderate Bakersfield assemblymember and physician, and progressive Randy Villegas, who earned Sen. Bernie Sanders’ endorsement.

District 40

This Southern California seat has the distinction of being the only California district made more Republican by Proposition 50.

Orange County Republican Rep. Young Kim currently holds it. But longtime Inland Empire Republican Rep. Ken Calvert plans to run there, setting up a potential clash between two strong GOP contenders.

While Kim is well-liked in her district, the redrawn 40th District actually has more of Calvert’s current turf than Kim’s.

“I believe Kim’s portion is about a third and Calvert’s portion is about half the district, so it makes sense that they would both want to run in this seat,” Covey said. “I think this will be a really competitive race.”

Kim, she said, is an incredibly strong fundraiser and campaigner.

“She has put up a really strong electoral performance in Orange County for the past couple of years for a Republican and has typically done better than Trump and won over Democratic voters,” Covey said.

But Calvert is also a “heavyweight,” she added, who will likely run to Kim’s right — and could perform well among the conservative voters in the district’s eastern swath.

“He’s chairman of the Appropriations Committee. He’s been around forever,” Covey said. “He was also someone who I was wondering if he was maybe going to retire. And I guess he feels like he’s in a position where still has a very good shot at winning this district, even against Young Kim.”

District 48

Speaking of retirements: All eyes are on longtime San Diego-area GOP Rep. Darrell Issa to see whether he stays in the newly drawn 48th District, which now slightly favors Democrats.

Issa could jump into the Kim-Calvert race in District 40 or lean on his immense personal wealth to compete in the new District 48, which now includes more of San Diego and liberal Palm Springs.

Whatever Issa decides, there will be plenty of competition on the other side of the aisle: Declared candidates include San Diego City Councilwoman Marni von Wilpert and former Obama administration official Ammar Campa-Najjar, who previously ran unsuccessfully twice for Congress.