U.S. District Judge Charles R. Breyer found that President Donald Trump and Defense Secretary Pete Hegseth violated federal law when they deployed thousands of National Guard troops and Marines to Los Angeles following immigration protests in June.
Judge Breyer determined that the Trump administration’s use of military personnel constituted systematic violations of the Posse Comitatus Act of 1878, a law that prohibits the use of federal military forces for domestic law enforcement purposes.
“The evidence at trial established that Defendants systematically used armed soldiers (whose identity was often obscured by protective armor) and military vehicles to set up protective perimeters and traffic blockades, engage in crowd control, and otherwise demonstrate a military presence in and around Los Angeles,” Breyer wrote. “In short, Defendants violated the Posse Comitatus Act.”
The suit was filed in June 2025 when Immigration and Customs Enforcement (ICE) initiated large-scale enforcement operations in Los Angeles, targeting areas with significant migrant populations. On June 6, ICE detained between 70 and 80 people and arrested 44, sparking immediate public protests.
The protests were managed by local law enforcement. The Los Angeles Police Department and Los Angeles Sheriff’s Department successfully maintained control, with LAPD making 29 arrests and declaring an unlawful assembly that dispersed most protesters by 11:00 p.m. on June 6.
Despite local authorities’ ability to handle the situation, President Trump issued a memorandum on June 7 calling the National Guard into federal service under 10 U.S.C. § 12406, citing “numerous incidents of violence and disorder” that threatened federal immigration enforcement.
The deployment was substantial: Secretary Hegseth federalized 4,000 California National Guard members and deployed approximately 700 U.S. Marines from Camp Pendleton, all placed under the control of Task Force 51. This occurred over the objections of California Governor Gavin Newsom and without meaningful coordination with state and local authorities.
The court found extensive evidence that Task Force 51 engaged in prohibited law enforcement activities across Southern California:
Los Angeles County Operations:
- Troops accompanied ICE officers on approximately 75% of their enforcement operations through mid-July
- Marines detained a veteran at the Wilshire Federal Building for 25 minutes using flex cuffs
- Task Force 51 participated in Operation Excalibur at MacArthur Park, described as a “show of presence” to “demonstrate federal reach and presence”
Operations Beyond Los Angeles:
- Mecca, Riverside County: Over 300 troops deployed to support 200 federal agents at a marijuana farm, establishing security perimeters with riot shields despite no specific threat
- Carpinteria, Santa Barbara County: 100-120 troops set up traffic control points to expedite federal operations at a cannabis farm
- Camarillo, Ventura County: Approximately 80 troops assisted with crowd control and perimeter security
The Trump administration argued that the President has inherent constitutional authority to protect federal property, personnel, and functions—a “constitutional exception” to the Posse Comitatus Act. Judge Breyer firmly rejected this argument, calling it contrary to Supreme Court precedent established in Youngstown Sheet & Tube Co. v. Sawyer (1952).
“Defendants’ arguments mirror those that President Truman made in 1952, and they cannot be squared with Youngstown,” Breyer wrote, emphasizing that the President cannot override Congress’s legitimate exercise of authority through claims of inherent executive power.
The court found that the violations were deliberate and systematic. Evidence showed that:
- Military officials were “coached” on what language to use in requests for assistance to circumvent the Act
- Troops were explicitly trained that certain law enforcement functions were permissible under a supposed “constitutional exception”
- The Department of Defense instructed troops they could engage in “crowd control, traffic control, security patrols, and riot control”
- Federal agencies gave local law enforcement only two hours’ notice of major operations like Operation Excalibur
Judge Breyer’s ruling addressed fundamental questions about the balance of power between federal and state governments and the separation of powers between Congress and the Executive. The court found that California suffered injury to its role in the federal system, as law enforcement is traditionally a state function.
“President Trump and Secretary Hegseth have stated their intention to call National Guard troops into federal service in other cities across the country—including Oakland and San Francisco, here in the Northern District of California—thus creating a national police force with the President as its chief,” Breyer warned.
While granting California’s request for injunctive relief, Judge Breyer stayed his ruling until September 12, 2025, allowing the Trump administration time to appeal. The injunction prohibits the deployment or use of National Guard troops in California for law enforcement activities including arrests, searches, traffic control, and crowd control unless authorized by a valid constitutional or statutory exception.
Approximately 300 National Guard members remain deployed in Los Angeles as of the ruling date, with their deployment extended through November.
The ruling comes as Trump has deployed National Guard troops to Washington, D.C., and threatened similar deployments to Chicago, Baltimore, Oakland, and San Francisco. The decision could significantly limit the administration’s ability to use military forces for domestic law enforcement in other cities.
The Trump administration is expected to appeal the decision to the U.S. Court of Appeals for the Ninth Circuit, which previously stayed an earlier ruling by Judge Breyer regarding the National Guard deployment.
