A federal judge in San Francisco has ruled that President Donald Trump’s deployment of National Guard troops and U.S. Marines to Los Angeles in response to immigration protests violated the Constitution. U.S. District Judge Charles Breyer determined that the administration’s actions breached the Posse Comitatus Act, a 19th-century law restricting the use of military forces in domestic law enforcement.
In his 52-page opinion, Judge Breyer stated, “There were indeed protests in Los Angeles, and some individuals engaged in violence. Yet there was no rebellion, nor was civilian law enforcement unable to respond to the protests and enforce the law.” He emphasized that the deployment of approximately 4,000 National Guard troops and 700 Marines in early June 2025 was not justified under the circumstances. ([calmatters.org](https://calmatters.org/justice/2025/09/trump-national-guard-posse-comitatus/?utm_source=openai))
The ruling prohibits the federal government from using military personnel for law enforcement activities in California, including arrests, crowd control, and traffic management. Judge Breyer’s order is set to take effect on September 12, allowing time for the administration to appeal. ([reuters.com](https://www.reuters.com/legal/government/us-judge-blocks-trump-administrations-use-troops-la-2025-09-02/?utm_source=openai))
California Attorney General Rob Bonta welcomed the decision, stating, “With today’s decision, Trump is barred from using the National Guard and Marines in California for law enforcement purposes.” ([calmatters.org](https://calmatters.org/justice/2025/09/trump-national-guard-posse-comitatus/?utm_source=openai)) Governor Gavin Newsom also praised the ruling, highlighting the importance of upholding states’ rights and the limitations on federal authority. ([axios.com](https://www.axios.com/local/san-francisco/2025/09/02/california-trump-national-guard-newsom-la-sf-ruling?utm_source=openai))
The Trump administration defended the deployment, arguing it was necessary to protect federal personnel and property during the protests. However, Judge Breyer found that the military’s involvement in activities such as setting up security perimeters and detaining civilians exceeded legal limits. ([reuters.com](https://www.reuters.com/legal/government/us-judge-blocks-trump-administrations-use-troops-la-2025-09-02/?utm_source=openai))
This ruling may have broader implications for the administration’s plans to deploy troops to other cities, including Chicago and Baltimore, as part of its campaign against crime and immigration violations. ([apnews.com](https://apnews.com/article/d6c8450a3ac2de34e669ef0836d22cbc?utm_source=openai)) The White House has signaled its intention to appeal the decision, maintaining that the deployment was within the president’s authority.
The case underscores the ongoing tension between federal and state authority, particularly concerning the use of military forces in domestic law enforcement. Legal experts suggest that this decision could set a precedent for future disputes over the federal government’s role in managing civil unrest and enforcing immigration laws within individual states.