Is Donald Trump’s Troop Deployment to Los Angeles Legal?

A federal judge issued an order to block Donald Trump from deploying California National Guard troops to crack down on Los Angeles protests or to stand guard over his immigration raids. 

Ruling Thursday night, United States District Judge Charles Breyer found that “an injunction restraining the president’s use of military force in Los Angeles is in the public interest” and ordered Trump to return control of thousands of National Guard troops to Gov. Gavin Newsom. 

The injunction came in response to a California lawsuit claiming Trump is violating bedrock American law and the constitution. However, the president’s commitment of 700 Marines to the streets of L.A. is apparently unaffected.

The ruling was met by an emergency appeal by the Trump administration to the Ninth Circuit court of appeals, which has now stayed the lower court’s injunction until at least June 17.

The back-and-forth court battle over Trump’s troop deployments poses a thorny question: Can the president of the United States really unleash the military on U.S citizens?

Here’s what you need to know:

Why is Trump doing this?

Trump, an authoritarian, has long dreamed of using the military to counter his domestic opposition. The pretext for Trump’s move is unrest following protests against Immigration and Customs Enforcement raids. ICE agents have been making provocative arrests and detentions of community members in Los Angeles, including of garment workers downtown and day laborers at an area Home Depot. 

These protests were largely peaceful, but in several locations, devolved into skirmishes between agitators on one side and cops, sheriff’s deputies, and/or paramilitary federal agents on the other. The unrest had largely calmed over the weekend, until Trump  decided to federalize units of the California National Guard and send them to the streets of L.A.

How many troops has Trump sent to Los Angeles?

Trump mobilized as many as 4,000 members of the California National Guard along with 700 Marines to deploy in Los Angeles. The military described the National Guard’s mission as “protecting federal personnel and federal property in the greater Los Angeles area.”

Is that legal? What about “Posse Comitatus”?

The Posse Comitatus Act stands as America’s legal guarantee against military occupation.

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Like so much of American history, passage of the Posse Comitatus Act is tarnished by racism. This law dates from the late 1870s. It was born out of backlash to Reconstruction in the South after the Civil War, at a time when former Confederates bridled under occupation by federal troops. These forces, for example, ensured access to the ballot box by Black voters. 

The act’s passage barred the Army from being deployed in a domestic law enforcement capacity; it effectively ended Reconstruction and ushered in decades of Jim Crow segregation in the South. 

Over time, the law’s restriction on the standing military being deployed inside the United States became bedrock U.S. law and a marker of state sovereignty. It is seen as a vital check on authoritarian abuses by a U.S. president, and it allows the military to focus on defeating foreign adversaries, leaving policework to cops. The act has been updated periodically, including as recently as 2021 to clarify that its restrictions apply even to the Space Force.

(The phrase “Posse Comitatus” itself is Latin for “power of the county” and has a complicated legacy dating back to English common law.) 

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How did Trump justify federalizing the National Guard?

National Guard forces are usually under the control of state governors. They have long played a role in responding to state-level natural disasters and public unrest. Under state control, National Guard forces are not restricted by the Posse Comitatus Act. 

State-ordered National Guard deployments have also been controversial. In one of the darkest episodes in recent American history, National Guard troops, called up by the Governor of Ohio to crack down on protesters at Kent State in 1970, opened fire on anti-war activists, killing four and injuring nine.

To federalize the National Guard, as Trump did this over the weekend, the president invoked an authority established in Title 10 of the federal code. Under that provision, the National Guard may be pressed into federal service under one of three conditions: 

In any of these cases, the president “may call into federal service” the requisite National Guard forces to “repel the invasion, suppress the rebellion, or execute those laws.” Invocation of this provision has little case history; Richard Nixon used it to call in the National Guard to deliver mail during a postal strike in 1970.

But in all cases, the statute states, orders to the National Guard “shall be issued through the governors of the states” — appearing to require agreement between the president and the governor, which does not exist in this case.

How has California contested Trump’s National Guard deployment?

The state of California sued in federal court in San Francisco to block Trump’s National Guard deployment as “unlawful,” insisting his Title 10 authority is a nonstarter in the case of the Los Angeles protests. 

“To put it bluntly, there is no invasion or rebellion in Los Angeles,” the lawsuit states. It describes instead common “civil unrest” that should be handled by “state and local authorities.” The lawsuit underscores that Gov. Newsom was not a party to Trump’s decision to federalize the National Guard: “The governor never issued such an order or gave consent.”

California is making the case that troops under Trump’s command are already unlawfully integrated into a policing function. “Military forces are pervasively intertwined with civilian law enforcement activities,” the latest update to suit argues. “Armed troops are working side by side with ICE agents in conducting arrests and raids in the streets, homes, and workplaces of Los Angeles.”

In the court of public opinion, the state is highlighting past comments by Trump and members of his cabinet to argue that administration officials know what they’re doing is illegal. A post on the governor’s website, calls back to Trump’s comments during the 2020 federal incursion into downtown Portland, Oregon. “We have to go by the laws,” Trump said at the time. “We can’t call in the National Guard, unless we are requested by a governor.”

Likewise Kristi Noem, Trump’s Homeland Security Secretary, said in 2024 as governor of South Dakota that a president seizing control of National Guard forces would be an unacceptable affront: “If Joe Biden federalizes the National Guard,” she said, “that would be a direct attack on states’ rights.”

What did the federal district judge decide?

In deciding to impose an injunction, Judge Breyer wrote that California had “shown a likelihood of prevailing” on their argument that Trump’s federalization of the National Guard was “not in fact not lawful, both exceeding the scope of his authority and violating the Tenth Amendment.” (The judge leaned hard on the that amendment which reserves many powers for the states: “It is well-established that the police power is one of the quintessential powers reserved to the states by the Tenth Amendment,” he wrote.)

Breyer recognized that the Trump administration has an ““interest in protecting federal agents and property” but insisted that the “the citizens of Los Angeles face a greater harm from the continued unlawful militarization of their city.” He added that the state faces harm of being deprived of “thousands of National Guard members to fight fires, combat the fentanyl trade, and perform other critical functions.” 

The judge underscored as well that that Trump’s troop deployment threatens to “chill legitimate First Amendment expression.” He wrote that he was “troubled” by the administration’s stance that “protest against the federal government, a core civil liberty protected by the First Amendment, can justify a finding of rebellion.”

The temporary injunction forbids Trump from calling up the National Guard and directs Trump to return control over these forces to Newsom.

Is that order being carried out?

The ruling by the district judge was immediately appealed to the Ninth Circuit, which quickly stayed the injunction Thursday, pending a hearing Tuesday, June 17.

What about Trump’s decision to deploy Marines?

It is unclear what authority Trump has invoked to deploy active duty Marines to Los Angeles. A statement by U.S. Northern Command says the Marines’ mission is to “seamlessly integrate with the Title 10 forces” — i.e. the National Guard troops.

The state of California lawsuit claims the Marine mobilization is a violation of Posse Comitatus. (It also argued that using federalized National Guard troops as military police violates that act.)

The suit reads, in part: “The Marine Corps’ deployment for law enforcement purposes is… unlawful. For more than a century, the Posse Comitatus Act has expressly prohibited the use of the active duty armed forces and federalized national guard for civilian law enforcement.” 

The judge in San Francisco did not make any ruling as to the Posse Comitatus Act arguments “at this early moment in the litigation,” explaining that both parties would soon have an opportunity to make their arguments in court.

What about the Insurrection Act?

The nativist Trump White House adviser Stephen Miller has been posting incessantly on X about the unrest in Los Angeles as an “insurrection.” Trump has also called protesters “insurrectionists.”

This over-the-top rhetoric has dangerous implications. 

The president has a trump card he can play if he seeks to expand this foray into martial law. That is the Insurrection Act. This law gives the president authority to side-step the restrictions of Posse Comitatus and to direct active duty military to suppress insurrection, domestic violence, and even “unlawful obstructions, combinations, or assemblages.” 

The act was pieced together from 1792 to 1871, and the liberal Brennan Center for Justice describes it as so “poorly” crafted and “bafflingly broad” as to “leave virtually everything up to the discretion of the president.”

The law is contradictory. Some provisions require the participation of the governor and/or legislature in the target state. Other parts give the president sole decision-making power. 

The Insurrection Act has been used both ways. It was famously invoked by President Dwight Eisenhower to enforce desegregation in the South after the Supreme Court decision in Brown v. Board of Education. Its most recent use was in Los Angeles in 1992, by President George H.W. Bush, during the Rodney King riots — a move requested by the state. Lyndon B. Johnson was the last president to invoke it against the wishes of a governor, sending in troops to protect Civil Rights marchers in segregationist Alabama in 1965.

Trump has been coy so far about his intentions, saying of the act from the Oval Office this week: “If there’s an insurrection, I would certainly invoke it. We’ll see.”

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What would that mean for democracy?

Under Trump, any invocation of the Insurrection Act would mark a dangerous step on a path toward dictatorship. In theory, the law only empowers the president to use federal military might to support local law enforcement, or ensure that the constitutional rights of citizens are defended, not to implement martial law. 

In practice, Trump was given near-kingly authorities last year by the Supreme Court in its immunity decision that shields the president from criminal prosecution. His administration has threatened to arrest Gov. Newsom, and even handcuffed one of the state’s U.S. Senators, Alex Padilla, when he attempted to ask Noem a question during a press conference, during which the Homeland Security secretary proclaimed that the federal government was on a mission to “liberate” Los Angeles, from the “socialist” leadership of its mayor and governor.

Trump does not see himself bound by any precedent or legal norm. And he is plainly not grounded in reality, rather in delusions of grandeur. In posts on Truth Social, Trump has written of his militarization as an effort to “liberate Los Angeles from the Migrant Invasion.” On Wednesday he doubled down, adding: “If our troops didn’t go into Los Angeles, it would be burning to the ground right now.”