A federal judge on Tuesday declared that President Donald Trump’s deployment of National Guard troops and Marines in Los Angeles earlier this year breached a federal law that forbids the use of military forces as a domestic police unit.
District Judge Charles Breyer, sitting in San Francisco, issued an order stopping the federal government from employing military personnel in immigration operations or other law enforcement actions in California.
Breyer, appointed by former President Bill Clinton, wrote that Trump was acting as “a national police force with the President as its chief.”

The judge temporarily paused the order, which prevents further use of troops for law enforcement, until September 12. In June, Trump sent thousands of California National Guard members and Marines to Los Angeles in reaction to protests against his aggressive immigration raids across the city.
Breyer’s ruling followed a non-jury trial last month over California’s claim that federal troops accompanying law enforcement in and around Los Angeles violated the Posse Comitatus Act of 1878, which generally forbids soldiers from performing civilian law enforcement duties.
California’s lawyers pointed out during the trial that the number of troops Trump sent to Los Angeles exceeded the number deployed to Afghanistan three months after 9/11.
Legal analysts noted that by delaying his order until September 12, Breyer may be anticipating an appeal from the Ninth Circuit Court of Appeals or the Supreme Court.
Although the decision does not take immediate effect, it could influence how Trump uses the military in Washington, D.C., where he recently deployed hundreds of National Guard members to support federal agents.
Allegations of Violating Posse Comitatus
Trump justified the D.C. deployment by citing the need to control violent crime, even though police data show that crime rates are falling.
During the trial, California argued that deploying soldiers alongside police effectively gave them an “active, direct role” in enforcing laws, violating Posse Comitatus.
Evidence presented at the trial showed close collaboration between the military and law enforcement, including attending FBI briefings on upcoming arrests, setting up traffic blockades and barriers, and detaining citizens on at least two occasions.
Breyer wrote that federal troops acted under the orders of Trump and Secretary of Defense Pete Hegseth. “Defendants systematically used armed soldiers, often with obscured identities due to protective armor, and military vehicles to establish perimeters and traffic blockades, engage in crowd control, and display military presence in and around Los Angeles,” Breyer stated. He added, “In short, Defendants violated the Posse Comitatus Act.”
DOJ Defense and Presidential Authority
Department of Justice lawyers argued that Trump did not breach Posse Comitatus because he was exercising his “protective power,” which they claim is a constitutional authority to use the military to protect federal property, personnel, and functions.
The DOJ described this power, which is based on legal interpretation of the Take Care Clause rather than explicit text in the Constitution, as an exception to Posse Comitatus that allows troops to carry out certain activities normally prohibited by the act.
During the trial, Breyer questioned the DOJ repeatedly, asking if there were any real limits on the president’s ability to deploy the military in support of law enforcement. DOJ attorneys did not specify any restrictions but insisted that the president’s protective power overrides Posse Comitatus.

Trump’s Federalization of California Troops
Trump mobilized the California National Guard after federalizing the troops over the objections of Governor Gavin Newsom, using an obscure federal statute. California sued, claiming that Trump’s mobilization order violated the law.
Breyer initially agreed with the state and issued a temporary restraining order blocking Trump from using California troops, but an appeals court later stayed the order, allowing the president to continue the deployment.
Since June, approximately 5,000 National Guard soldiers and Marines have been sent to southern California, assisting with over 170 federal law enforcement operations, including routine Drug Enforcement Administration counter-drug raids conducted hundreds of miles from Los Angeles. While many of the troops have returned, hundreds remain active in the city.
Trump also threatened to deploy soldiers to other Democratic-run cities, including New York, Baltimore, Chicago, and Oakland, while announcing the D.C. deployment.