San Diego City Councilmember Marni von Wilpert has won California's 48th Congressional District, defeating San Diego County Supervisor Jim Desmond, according to The Associated Press as reported by KPBS.

The victory flips the North County seat from Republican to Democratic hands. As of 1 a.m. Wednesday, Nov. 4, with 73 percent of the vote counted, von Wilpert led 59 percent to 41 percent, according to Voice of San Diego.

All five of San Diego County's congressional delegates will now be Democrats, KPBS reported. Von Wilpert joins Reps. Mike Levin, Scott Peters, Sara Jacobs and Juan Vargas in the delegation.

Von Wilpert addressed supporters at a packed event in San Marcos on election night. She framed the win as a rebuke of the Trump administration and U.S. Immigration and Customs Enforcement.

"I am so glad that our nation chose love over fear," von Wilpert said, according to KPBS. "Yes, when it comes to these horrific ICE raids, we're going to stop ICE from tearing our communities apart."

In a statement released Tuesday, Nov. 3, von Wilpert said she would represent all constituents regardless of how they voted, Fox 5 San Diego reported.

Desmond, who carried an endorsement from President Donald Trump, was asked about early results before von Wilpert declared victory. He said it was too early to tell and that he was not giving up, according to KPBS.

How the district changed

The 48th District was one of five Republican-held congressional seats targeted by Proposition 50, which California voters approved in a special election in November 2025. The measure temporarily redrew the state's congressional map to give Democratic candidates an advantage, a response to what Gov. Gavin Newsom called an effort to "fight fire with fire" against pro-Republican redistricting in Texas, KPBS reported.

Before Prop. 50, registered Republicans outnumbered Democrats in the 48th. The new lines reversed that balance, according to KPBS. The redrawn district moved west and north, adding the North County cities of Escondido, San Marcos and Vista, CalMatters reported in November 2025.

Rep. Darrell Issa, who held the seat, chose not to seek reelection in the redrawn district, according to Voice of San Diego.

What comes next

The results remain unofficial until the canvass is complete on or before Dec. 3, according to Times of San Diego.

Von Wilpert's departure from the San Diego City Council, where she represents District 5, will trigger a special election. The Office of Council President Joe LaCava said in a press release that the council would set an election date once the seat is officially vacated, Fox 5 reported.

The governor and Legislature have pledged that the independent redistricting process will proceed as normal at the end of the decade, Voice of San Diego noted. That could make the 48th more competitive again in future cycles.