California National Guard Lawsuit: Posse Comitatus Trial and Outcome

The California National Guard lawsuit, Newsom v. Trump, was filed by Governor Gavin Newsom and Attorney General Rob Bonta on June 9, 2025, after President Trump federalized roughly 4,000 California Guard members and deployed them, along with 700 Marines, to Los Angeles without the governor’s consent. California argued the takeover was illegal under 10 U.S.C. § 12406, the Posse Comitatus Act, and the Tenth Amendment. Federal courts largely agreed: a district judge ruled the deployment violated the Posse Comitatus Act in September 2025, issued a preliminary injunction ending the federalization in December 2025, and on December 31, 2025, Trump announced he was pulling the Guard out of Los Angeles.

Why the Guard Was Federalized

On June 6, 2025, Immigration and Customs Enforcement conducted sweeps in downtown Los Angeles, arresting people at an apparel manufacturer and a Westlake-area Home Depot. Large protests followed near the Edward R. Roybal Federal Building, with additional unrest in Paramount and Compton. Demonstrators blocked the 101 Freeway, set vehicles on fire, and threw rocks, bottles, Molotov cocktails, and fireworks at law enforcement. On June 9 alone, 197 people were arrested and 23 businesses were looted.¹

On June 7, President Trump signed a memorandum invoking 10 U.S.C. § 12406 and authorizing 2,000 National Guard members to deploy to Los Angeles. He described the protesters as “paid insurrectionists” and framed the unrest as a rebellion against federal authority. By June 10, the Defense Department had added 700 active-duty Marines and another 2,100 Guard troops. At its peak the federal government commanded 4,119 California Guard members, roughly a third of the Guard’s active strength.¹² It was the first time since the 1960s the National Guard had been deployed over a governor’s objection.³

What California Argued Was Illegal

The complaint, filed in the U.S. District Court for the Northern District of California as Case No. 3:25-cv-04870, went before Senior Judge Charles R. Breyer.⁴⁵ California made three central claims.

First, the state argued the federalization exceeded statutory authority. Section 12406 permits the president to call up the Guard only when the country is invaded, when there is a rebellion, or when regular forces cannot execute federal law. California said none of these conditions existed. The state also alleged the administration ignored the statute’s requirement that orders be issued “through the governors of the States,” and that the deployment violated the Posse Comitatus Act’s general prohibition on using the military for domestic law enforcement.⁶

Second, California claimed a Tenth Amendment violation: the federalization stripped the governor of command over state military forces.⁶ Third, the state argued the Defense Department failed to follow procedures required by the Administrative Procedure Act.⁴

The administration’s defense rested on presidential discretion. Citing the 1827 Supreme Court decision Martin v. Mott, government lawyers argued the president is the “sole and exclusive judge” of whether a rebellion exists and whether regular forces are sufficient, with his determination immune from judicial review. The administration also claimed troops were exercising an inherent Article II “protective power” to safeguard federal property and personnel, which it said fell outside the Posse Comitatus Act entirely.⁶⁷

The Early Rulings

On June 12, 2025, Judge Breyer granted a temporary restraining order. He rejected the political-question defense, holding that courts retain the duty to determine whether § 12406’s preconditions have been met. He found no evidence of rebellion and no showing that regular federal forces could not execute the law. The order directed the president to “return control of the California National Guard to the Governor of the State of California forthwith” and called the federalization “illegal—both exceeding the scope of his statutory authority and violating the Tenth Amendment.”⁶

The Ninth Circuit intervened the same day. A three-judge panel of Mark J. Bennett, Eric D. Miller, and Jennifer Sung stayed Breyer’s order, saying judicial review of a president’s § 12406 determination must be “highly deferential.” Under that standard, the panel found the administration had shown a “colorable basis” for invoking the statute. The stay allowed the Guard to remain in Los Angeles while the case proceeded.⁸

The Posse Comitatus Trial

Judge Breyer held a three-day bench trial from August 11 to 13, 2025, on whether military activities violated the Posse Comitatus Act. Evidence showed federalized Guard troops performing security patrols, traffic control, crowd control, and riot control. In one incident in Carpinteria, troops were filmed physically turning away a civilian at a traffic blockade. In Los Angeles, troops participated in “Operation Excalibur,” described in internal records as a demonstration of “federal reach and presence” at a location where no threats to federal functions had been identified.⁷

Testimony showed that a Task Force 51 official, William Harrington, had warned at a June 7 briefing that federalized Guard troops would lose law-enforcement authority under the Posse Comitatus Act, and that the commanding general agreed. Troops were nevertheless told orally by the Defense Department that a “constitutional exception” permitted security and crowd control functions. Internal communications also showed the Defense Department had coached federal agencies to substitute the word “protection” for “security” in requests for military assistance.⁷

On September 2, 2025, Judge Breyer ruled that the deployment violated the Posse Comitatus Act. He found Guard units had engaged in prohibited law-enforcement activities under a “top-down directive” and rejected the administration’s inherent “protective power” theory as “not grounded in the history of the [Posse Comitatus Act], Supreme Court jurisprudence on executive authority, or common sense.” He wrote that the administration was attempting to “create a national police force with the President as its chief.” His injunction barred the use of the Guard or any military troops in California for arrests, searches, seizures, security patrols, traffic and crowd control, evidence collection, interrogation, and acting as informants.⁹¹⁰ The administration appealed, and the Ninth Circuit again granted an administrative stay.¹¹

How the Supreme Court’s Ruling Changed the Case

As the California case moved through appeal, the administration attempted similar deployments in Oregon, Illinois, and Washington, D.C. The Illinois case reached the Supreme Court. On December 23, 2025, the Court issued a three-page unsigned order in Trump v. Illinois (No. 25A443), denying the administration’s request to stay a district court order blocking federalization of the Illinois Guard. The vote was 6-3.¹²

The majority held that “regular forces” in § 12406 “likely refers to the regular forces of the United States military.” Before federalizing the Guard, the president had to show he was unable to execute the laws using active-duty troops. And because the Posse Comitatus Act generally forbids using the military for law enforcement, the government first had to identify a legal basis for using the military in that role. The Court said the government had failed to do so. The ruling also exposed a contradiction in the administration’s position: if military “protective” activities did not amount to executing the laws, the president could not simultaneously claim he was unable to execute the laws as grounds for calling up the Guard. Justice Kavanaugh concurred separately. Justice Alito dissented in a 16-page opinion joined by Justice Thomas, and Justice Gorsuch filed a two-page dissent.¹³¹²

How the Deployment Ended

On December 10, 2025, Judge Breyer granted a preliminary injunction ordering the administration to end the federalization. He found no “colorable basis” to conclude the president was currently unable to execute the laws with regular forces, noting the protests had long since subsided and the deployment rested on “speculative future risks rather than a present exigency.” He rejected the government’s argument that extensions of the initial federalization were unreviewable, warning that such a reading would permit “indefinite federal control of state militias.” Enforcement was delayed until December 15 to give the administration time to respond.¹⁴²

By then the deployment had already shrunk. Though the force peaked above 4,100, only about 100 troops remained on the ground in Los Angeles by October 2025, and roughly 300 total remained under federal control by December, with others reportedly redirected to Chicago and Portland.²

On December 30, the Department of Justice filed a document stating it was no longer seeking a stay of Judge Breyer’s order. The next day, the Ninth Circuit formally vacated its stay, making the preliminary injunction fully operative.⁴ On December 31, Trump posted on Truth Social that he was “removing the Guard troops for now” from Los Angeles, Chicago, and Portland, adding, “We will come back, perhaps in a much different and stronger form, when crime begins to soar again.”¹⁵

Newsom rejected any framing of the withdrawal as voluntary. His spokesman Izzy Gardon called the announcement “the political version of ‘you can’t fire me, I quit.'” Newsom said: “I’m glad President Trump has finally admitted defeat: We’ve said all along the federalization of the National Guard in California is illegal.”¹⁶ Attorney General Bonta called the outcome a victory over “unlawful overreach of executive power.”¹⁷

What It Cost

The Defense Department initially estimated the deployment would cost $134 million over 60 days.¹⁸ Federal records obtained by the Governor’s office through a Freedom of Information Act request, released in May 2026, showed actual costs of at least $111.2 million across fiscal years 2025 and 2026, with final overtime and demobilization figures still outstanding.¹⁹

Where the Case Stands Now

As of mid-2026, Newsom v. Trump remains technically open in the district court, though the Guard has been returned to state control. On January 12, 2026, the parties filed a stipulated motion to stay deadlines on a pending motion to dismiss while awaiting Ninth Circuit guidance in light of Trump v. Illinois. The Ninth Circuit appeal (No. 25-5553) has been placed in abeyance, with status reports due every 60 days; the most recent was filed by California on May 12, 2026.¹¹⁴

Attorney General Bonta has said the combined precedent from the California, Oregon, Illinois, and D.C. cases effectively forecloses future unauthorized federalizations. He argued the administration would now have to prove that all available military forces were unable to maintain order before taking over a state’s Guard. “He’ll never be able to show that,” Bonta said. “The law got developed in a way that will prevent what happened over the last six months from ever happening again.”²⁰

1
ABC News. Timeline: ICE Raids Sparked LA Protests, Prompted Trump
2
CNN. Judge Blocks LA National Guard Deployment
3
American Immigration Council. Los Angeles, Chicago: Trump Deploys Troops in Immigration Crackdown
4
Civil Rights Litigation Clearinghouse. Newsom v. Trump
5
NPR. Marines, National Guard, Los Angeles: Trump Lawsuit
6
U.S. District Court, N.D. Cal. Newsom v. Trump, TRO Order
7
FindLaw. Newsom v. Trump, N.D. Cal.
8
U.S. Court of Appeals for the Ninth Circuit. Newsom v. Trump, Ninth Circuit Opinion
9
Office of Governor Gavin Newsom. Governor Newsom Secures Federal Court Victory
10
Lawfare. The Lingering Uncertainty in Judge Breyer’s Newsom v. Trump Ruling
11
CourtListener. Newsom v. Trump, Ninth Circuit Docket
12
SCOTUSblog. Supreme Court Rejects Trump’s Effort to Deploy National Guard in Illinois
13
U.S. Supreme Court. Trump v. Illinois, No. 25A443
14
Office of Governor Gavin Newsom. Federal Court to Trump: Keeping a Standing Army Is Illegal
15
PBS NewsHour. Trump Says He’s Dropping Push for National Guard in Chicago and Other Cities
16
The New York Times. Trump News
17
Politico. Donald Trump National Guard Deployment
18
PBS NewsHour. Hegseth Says Troops Could Be in LA for 60 Days, Cost $134 Million
19
Office of Governor Gavin Newsom. Trump Sticks Taxpayers With $111 Million Bill
20
CalMatters. Rob Bonta, National Guard Lawsuits