A US federal judge has ruled that President Donald Trump’s deployment of National Guard troops and Marines to Los Angeles in June was illegal, citing a violation of the 1878 Posse Comitatus Act.

Judge Charles Breyer of the US District Court for the Northern District of California stated that the administration had no authority to use the military to enforce domestic laws without congressional approval. The ruling permanently bars the federal government from “deploying, ordering, instructing, training, or using” the National Guard and other military forces in California for law enforcement.

The court noted that while protests over federal immigration raids in Los Angeles involved sporadic violence, they did not rise to the level of rebellion, nor did local law enforcement lose control. Despite this, around 300 National Guard members remained in Los Angeles months after the initial deployment. Breyer also pointed to Trump and Defense Secretary Pete Hegseth’s stated intent to expand such actions nationwide, effectively creating a “national police force” led by the president.

California Governor Gavin Newsom, a plaintiff in the case, welcomed the ruling: “Today, the court sided with democracy and the Constitution. No president is a king — not even Trump — and no president can trample a state’s power to protect its people.”

The White House criticized the ruling as judicial overreach, with Deputy Press Secretary Anna Kelly arguing it undermines the president’s duty to protect American cities. The Justice Department has filed an appeal and requested a stay on the order.

Legal experts say Breyer’s ruling could set a significant precedent for future cases involving presidential use of the military in domestic affairs.