Active-duty Marines deployed alongside the federalized Guard in Los Angeles

Editor's note: a federal court, after trial, held that deploying the Guard and Marines to Los Angeles to enforce federal law violated the Posse Comitatus Act.

Active-duty US Marines were deployed to Los Angeles alongside the federalized National Guard, tasked with what California's lawsuit characterized as unlawful civilian law-enforcement activities beyond simply guarding federal buildings.

Deploying active-duty Marines, not just National Guard, to an American city for what the court found was the purpose of establishing a military presence there and enforcing federal law, without the Insurrection Act invocation that would at least require the president to formally declare the legal basis, extended the military's domestic role further than the Guard federalization alone.

The September 2025 Posse Comitatus Act ruling found the deployment of the Guard and Marines to Los Angeles a serious violation of the Act, and its injunction reached any military troops deployed in California; it also found some individual Marine conduct, such as one detention at the Wilshire Federal Building, too isolated to violate the Act. The Pentagon ordered the Marines out of Los Angeles on July 21, 2025.