Donald Trump’s administration has ordered the deployment of 4,000 national guard members and 700 marines in response to protests against deportation operations in Los Angeles.
The deployment of soldiers into the city comes despite the objections of local officials and the California governor, and appeared to be the first time in decades that a president activated a state’s national guard without a request from its governor.
Governor Gavin Newsom has sued to block the use of military forces to accompany federal immigration enforcement in Los Angeles, calling it an “illegal deployment”.
“The federal government is now turning the military against American citizens. Sending trained warfighters on to the streets is unprecedented and threatens the very core of our democracy,” Newsom wrote.
Here are some things to know about when and how the president can deploy troops on US soil.
Generally, federal military forces are not allowed to carry out civilian law enforcement duties against US citizens except in times of emergency.
An 18th-century wartime law called the Insurrection Act is the main legal mechanism a president can use to activate the military or national guard during times of rebellion or unrest. But Trump didn’t invoke the Insurrection Act on Saturday.
Instead, he relied on a similar federal law that allows the president to federalize national guard troops under certain circumstances. Trump used Title 10 authority, which places him rather than the governor at the head of the chain of command, to call part of California’s national guard into federal service.
The national guard is a hybrid entity that serves both state and federal interests. Often, it operates under state command and control, using state funding. Sometimes national guard troops will be assigned by their state to serve federal missions, remaining under state command but using federal funding.
The law cited by Trump’s proclamation places national guard troops under federal command. The law says this can be done under three circumstances: when the US is invaded or in danger of invasion; when there is a rebellion or danger of rebellion against the authority of the US government; or when the president is unable to “execute the laws of the United States”, with regular forces.
But the law also says that orders for those purposes “shall be issued through the governors of the States”. It’s not immediately clear whether the president can activate national guard troops without the order of that state’s governor.
Trump has baselessly claimed paid “rioters bearing foreign flags with the aim of continuing a foreign invasion” are leading the protests in LA.
Trump’s proclamation said the national guard troops would play a supporting role by protecting US immigration officers as they enforce the law, rather than having the troops perform law enforcement work.
Steve Vladeck, a professor at the Georgetown University Law Center who specializes in military justice and national security law, says that’s because national guard troops can’t legally engage in ordinary law enforcement activities unless Trump first invokes the Insurrection Act, which authorizes the president to use military forces domestically in the event of an insurrection or rebellion.
Vladeck said the move raises the risk that the troops could end up using force while filling that “protection” role. The move could also be a precursor to other, more aggressive troop deployments down the road, he wrote on his website.
“There’s nothing these troops will be allowed to do that, for example, the ICE officers against whom these protests have been directed could not do themselves,” Vladeck wrote.
The 700 marines that arrived in the city on Tuesday were there to protect federal officials and property, and not to respond to the protests, the Marine Corps commandant said.
California’s attorney general, Rob Bonta, has said that the Trump administration intends to use “unlawfully federalized National Guard troops and Marines to accompany federal immigration enforcement officers on raids throughout Los Angeles”.
Pete Hegseth, the US defense secretary, said he expected the military would remain in the city for 60 days at a cost of at least $134m. He defended the deployment, telling a US House subcommittee on Tuesday that they were there “to maintain the peace on behalf of law enforcement officers in Los Angeles, which Gavin Newsom won’t do”, he said.
Peter Aguilar, US congressman for California’s 33rd district, asked about the justification for using “the military for civilian law enforcement purposes in LA”.
“Every American citizen deserves to live in a community that’s safe, and Ice agents need to be able to do their job. They’re being attacked for doing their job, which is deporting illegal criminals. That shouldn’t happen in any city, Minneapolis or Los Angeles, and if they’re attacked, that’s lawless,” Hegseth replied.
For his part, Trump has said his administration had “no choice” but to send in troops, and argued that his decision “stopped the violence”.
California leaders, meanwhile, have countered that the administration’s moves are intentionally inflammatory and that the Trump administration is using Los Angeles as an “experiment”.
The Insurrection Act and related laws were used during the civil rights era to protect activists and students from desegregating schools. Dwight Eisenhower sent the 101st airborne to Little Rock, Arkansas, to protect Black students integrating Central high school after that state’s governor activated the national guard to keep the students out.
George HW Bush used the Insurrection Act to respond to riots in Los Angeles in 1992 after the acquittal of white police officers who were videotaped beating Black motorist Rodney King.
National guard troops have been deployed for a variety of emergencies, including the Covid pandemic, hurricanes and other natural disasters. But generally, those deployments are carried out with the agreements of the governors of the responding states.
In 2020, Trump asked governors of several states to deploy their national guard troops to Washington DC to quell protests that arose after George Floyd was killed by a Minneapolis police officer. Many of the governors agreed, sending troops to the federal district.
At the time, Trump also threatened to invoke the Insurrection Act for protests following Floyd’s death in Minneapolis – an intervention rarely seen in modern American history. But then defence secretary Mark Esper pushed back, saying the law should be invoked “only in the most urgent and dire of situations”.
Trump never invoked the Insurrection Act during his first term.
But while campaigning for his second term, he suggested that would change. Trump told an audience in Iowa in 2023 that he had been prevented from using the military to suppress violence in cities and states during his first term, and said that if the issue came up again in his next term: “I’m not waiting.”
Trump also promised to deploy the national guard to help carry out his immigration enforcement goals, and his top adviser, Stephen Miller, explained how that would be carried out: sympathetic Republican governors would send troops to nearby states that refused to participate, Miller said on The Charlie Kirk Show in 2023.
After Trump announced he was federalizing the national guard troops on Saturday, the defence secretary Pete Hegseth said other measures could follow.
Hegseth wrote on the social media platform X that active-duty Marines at Camp Pendleton were on high alert and would also be mobilized “if violence continues”.
