Marines now stationed on the California border. Newsom’s office calls it ‘mission creep’

Dozens of Marines are now stationed at a Border Patrol station in eastern San Diego County, a new development that points to the Trump administration’s military buildup on the southern border. Some Marines there told CalMatters on Wednesday that they are out in Campo patrolling the border twice a day.

That’s a change from how Marines have operated in Southern California since President Trump took office. Until now, Marines have been limited to a supporting role, adhering to the Posse Comitatus Act of 1878, which keeps the armed forces away from civilian law enforcement.

But Trump has long hinted at using the armed forces in unprecedented ways at the border to deal with what he describes as “an invasion.”

And recently, the Trump administration shifted immigration enforcement northward toward the interior of California. Border Patrol agents have been seen chasing farmworkers through strawberry fields in Oxnard and swarming workers in unmarked cars at bus stops in inner-city Los Angeles.

The Marines have not disclosed detaining anyone in California. Active-duty Army soldiers patrolling the border in New Mexico earlier this month reported turning people over to immigration authorities, a change that illustrated escalating immigration enforcement by military service members.

A spokesperson for Newsom in a written statement to CalMatters connected the Marines at Campo to the Trump administration sending Border Patrol agents hundreds of miles inland.

"Now it appears Marines are being forced to backfill those border slots,” she continued. “This is not just mission creep—it’s putting law enforcement, our soldiers, and the community in danger.”