Long-serving Republican Congressman Darrell Issa announced Friday he will not seek re-election in California's newly redrawn 48th Congressional District, throwing his endorsement behind San Diego County Supervisor Jim Desmond in what's shaping up to be one of the region's most closely watched political races of 2026.

Issa, who has represented the district for over two decades, cited the district's redrawing under Proposition 50 — California's redistricting response to congressional map changes in other states — as a factor in his decision. Despite early polling that suggested he could win, Issa said he is ready for "a new chapter and new challenges."

"Serving in Congress has been the honor of my life," Issa said in a statement. "Jim is not only a personal friend, he's a true patriot, a Navy veteran, a successful businessman, and has a 20-year record of public service. He understands this community, was born and raised here, and will make a terrific Congressman."

Desmond, who has served as both the mayor of Vista and a San Diego County Supervisor, announced his candidacy for the 48th District minutes before Issa's retirement statement was released. The newly configured district includes a large portion of San Diego County's northeastern region — encompassing East County communities including Santee — along with portions of Riverside County.

Democrats immediately signaled they plan to compete hard for the seat. The Democratic Congressional Campaign Committee called Issa's departure an opportunity, and San Diego City Council Member Marni Von Wilpert announced her own candidacy, framing the race as a chance to flip the district. Political observers note the redrawn boundaries under Prop 50 make the seat more competitive than it has been in recent cycles. The outcome will directly affect federal representation for Santee and surrounding East County communities.