A federal judge has dealt President Donald Trump a major legal defeat, ruling that his deployment of thousands of National Guard troops and Marines to Los Angeles earlier this year violated federal law.
U.S. District Judge Charles Breyer issued the decision September 2, finding that the operation breached the Posse Comitatus Act, the 150-year-old statute prohibiting federal troops from engaging in domestic law enforcement. The case arose from a lawsuit filed by California Governor Gavin Newsom, who accused the Trump administration of using the military to police protests against immigration enforcement.
Charles Breyer is the brother of former liberal Supreme Court Justicie Stephen Breyer, who once suggested that Trump should be jailed for enforcing immigration laws.
The ruling capped a contentious three-day trial in August where Breyer pressed administration lawyers on the scope of presidential authority, writes Fox News. “I go back to the thing that I’m really troubled by: What limiting factors are there to the use of this force?” the judge asked. In a 52-page opinion, he concluded that the troops had been deployed not simply to protect federal property but to perform law enforcement functions — establishing perimeters, controlling crowds, and reinforcing federal immigration raids.
Trump ordered the deployment in June, federalizing roughly 4,000 National Guard members and adding 700 Marines. Although most forces were later withdrawn, about 300 Guard troops remained in Los Angeles. California argued that was enough to constitute a violation, and Breyer agreed. “That’s certainly a large enough number of soldiers to constitute a Posse Comitatus Act violation,” a state attorney said during the trial.
Breyer’s injunction prohibits Trump and Defense Secretary Pete Hegseth from using military personnel in California for arrests, searches, or crowd control. While limited to one state, the order carries national implications as the administration has signaled plans to send Guard units to other Democratic-led cities. Breyer warned that such moves risk “creating a national police force with the President as its chief.”
Governor Newsom quickly claimed victory, writing on social media: “CALIFORNIANS JUST BEAT TRUMP IN COURT (AGAIN!) — bringing much needed accountability and oversight to the Trump Admin’s ILLEGAL militarization of Los Angeles.”
🚨 CALIFORNIANS JUST BEAT TRUMP IN COURT (AGAIN!) — bringing much needed accountability and oversight to the Trump Admin’s ILLEGAL militarization of Los Angeles.
“The Court ORDERS that Defendants [TRUMP] are enjoined from deploying, ordering, instructing, training, or using the… pic.twitter.com/k9VqbbaaoD
— Governor Newsom Press Office (@GovPressOffice) September 2, 2025
The Trump administration argued that the president’s constitutional duty to protect federal property and personnel superseded the Posse Comitatus Act. Breyer rejected that defense, citing testimony from Major General Scott Sherman, who confirmed that Guard units had received training on the act’s restrictions.
The administration is expected to appeal to the Ninth Circuit. Though the immediate impact is limited, the ruling underscores the enduring tension between state sovereignty and federal power — and revives a longstanding American debate over the role of the military in domestic affairs.
