California voters approved Proposition 50 in November. The ballot measure redrew the state’s congressional districts ahead of the 2026 midterm elections.
The biggest impact in the San Diego region will be on the 48th District, which is currently held by Republican Rep. Darrell Issa. His district is changing in a big way, and the balance of voter registration in the new district now favors a Democratic challenger.
Below is an interactive map that shows how Prop 50 impacted San Diego’s five congressional districts. Toggle the map to see what they looked like before and after Prop. 50. Select a district to see the before-and-after overlaid on the map.
Voting patterns have also shifted in San Diego County over the past few elections. Between the Governor recall election in 2021 and the Presidential election in 2024, several places in San Diego County shifted to the right, as seen in a 2025 KPBS analysis.
But many of those places shifted back in the 2025 special election and voted in favor of Prop 50, which was seen as a referendum on the Trump administration. The map below allows users to explore voting patters around San Diego County across the three election cycles.
KPBS and inewsource spoke with voters and party leaders from three affected areas in the county about the impact of Prop 50’s new map on their communities and voting patterns.
Fallbrook
Fallbrook is now mainly in the 49th District but parts remain in the 48th. Republican Rep. Darrell Issa currently represents the 48th, and Democratic Rep. Mike Levin represents the 49th.
The north-eastern portion of Fallbrook is the only part of the city to remain in District 48 after the redistricting. Here, a majority of voters here said “no” on Prop 50.
The only areas in Fallbrook where a majority of voters were in favor of redistricting were in and around the city’s downtown, which is now part of the 49th District.
Cole Marting is a Fallbrook resident and the Executive Director of the San Diego Young Republicans. He said his group did not think California needed to combat the redistricting first done in Texas. Marting expressed concerns about his area being split into two districts, with most of Fallbrook now sharing a district with coastal cities.
“Prop 50 may have been well-intentioned by the left, right, but here in Fallbrook, the result is really just confusion, fragmentation, and a loss of identity,” Marting said. “It's really, really sad for this community and we're one that suffers because of Prop 50. At the end of the day, we need representation that understands rural needs.”
Ross Pike is the President of the Fallbrook Democratic Club. He said his group is advocating to elect Democrats for both Districts 48 and 49 in the midterm elections.
“Right now, our members are very motivated to retake the majority of Congress to be able to put up a front and stand up against the tyrannical methods that are being employed by the White House,” Pike said.
Poway
Poway was previously in the 48th District as well. After Prop 50, it now falls within the 50th District, currently held by Democratic Rep. Scott Peters.
The conservative group Rancho Bernardo Republican Women declined to comment. The North County Republican Women said they have no members in Poway and the San Diego County Republican club did not respond to a KPBS interview request.
Poway Democratic club President Amit Asaravala said that Poway is facing affordability issues, and his group is looking to elect representatives that will take action to address this. He said his group is also looking for representatives who will take a stand against “stronghold enforcement tactics” from U.S. immigration services.
Asaravala said Prop 50 was passed overwhelmingly, but reluctantly, as a countermeasure against Texas’s redistricting.
“We want to make sure that, as Texas redistricts, that we make sure that in California, the districts that essentially become swing districts now actually become Democratic so that we can counteract Texas,” Asaravala said.
Poway voters were almost exactly divided on Prop. 50, with slightly more people overall voting in favor of redistricting.
A slim majority of voters in northern Poway were not in favor of Prop. 50. Poway will now entirely be in a different district this year, as compared to the 2024 Presidential election.
Chula Vista
Taking a look toward southern San Diego County: Chula Vista, the county’s second-largest city, has also made some noticeable shifts in voter patterns.
In 2021, residents there overwhelmingly voted against recalling Newsom, joining much of the state in rejecting the ballot measure by a landslide. But Republicans saw some gains in 2024, when Trump gained about 7 percentage points in the city.
Come 2025, those gains took a hit. Chula Vista precincts showed more deep blue pockets in the Prop 50 vote compared to the presidential election.
Some Chula Vista residents say single-issue items can explain the shifts.
Angela Contreras, 34, pointed to the examples of “extreme” and “polarized” views toward Newsom during the 2021 recall vote; what she described as transphobic rhetoric from the White House; and now, the public’s response to the Trump administration’s massive deportation campaign and a U.S. Supreme Court decision permitting federal immigration officers to racially profile.
Contreras lives in west Chula Vista at the Vistan Apartments — an area that has consistently yielded a Democratic-majority vote for at least the past five years. She and her spouse, a disabled veteran, are Democrats.
“I know people that flipped as far as the presidential election went and it was very surprising to me,” Contreras said. “And all the reasons were cultural. They're all religion or beliefs. It wasn't ever really about infrastructure or government."
Leroy Jones, 70, remembers elections as far back as the Kennedy presidency. He’s lived to see numerous politicians on each side “play the games every year,” he said. He blames uninformed voters who elect them. People vote against their own interests, such as Medicare and social security, he said
“Nobody reads,” he told Public Matters partner inewsource. “Nobody takes their time to find out what the person is about. It's just like dating.”
Jones lives near the city’s Department of Motor Vehicles office and has voted for Democrats and third-party candidates.
While most of Chula Vista’s voters — and their City Council — are registered Democrats, they’re represented by Mayor John McCann, a Republican who is running for re-election this year.
“As Mayor and a lifelong resident of Chula Vista, I have always focused on what is best for the city and its residents,” he said in a statement to inewsource. “A pothole doesn’t have a party registration, we just need to get it fixed. I'll leave the partisan politics to others.
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As the maps show, voting patterns and voter behavior are difficult to predict. But who ends up winning these new congressional districts could decide control of the House of Representatives in 2027.
Democrats in San Diego see this as an opportunity to stop the Trump Administration’s agenda, if they can win control of at least one congressional chamber.
Challengers are already lining up to run in the new 48th, including Ammar Campa-Najjar, who challenged Issa in 2020 but lost by about 8% of the vote; and San Diego City Councilmember Marni Von-Wilpert, currently representing the 5th council district.
Rep. Issa did not respond to a request for comment, but said in an earlier statement, “I’m not going anywhere.”
“I’ll continue to represent the people of California — regardless of their party or where they live,” he said.
