When have presidents called in the National Guard to quell domestic unrest?

In the spring of 1992, Los Angeles was on fire. Dozens of people were killed, more than 1,500 people were injured and property damages were estimated to be about $500 million, as protests spread throughout the city after a jury acquitted police officers who beat Black motorist Rodney G. King.

President George H.W. Bush said he saw “the brutality of a mob, pure and simple.” Pledging to “use whatever force is necessary to restore order,” he ordered thousands of National Guard troops to Los Angeles to quell one of the city’s worst riots.

Thirty-three years later, National Guard members are back in Los Angeles, under different circumstances.

President Donald Trump on Saturday ordered 2,000 California National Guard troops to the city to intervene in protests against his administration’s immigration raids. But while Bush was acting on California officials’ request, Trump acted against the wishes of California Gov. Gavin Newsom (D), who said state and local authorities had the protests under control.

Newsom also said Sunday that he planned to sue the Trump administration for deploying the National Guard to Los Angeles, calling it “immoral” and “unconstitutional.”

“We didn’t have a problem until Trump got involved,” Newsom wrote on Twitter, sharing a letter he addressed to Defense Secretary Pete Hegseth in which he requested that the order to federalize the California National Guard be rescinded.

The National Guard is a reserve force of the U.S. military that can be called on by state governors or the president to respond to domestic emergencies or participate in overseas combat and civilian missions. U.S. presidents have also, rarely, federalized the National Guard to intervene in protests on U.S. soil. In 1794, President George Washington “called upon state militia and volunteer units to suppress” the Whiskey Insurrection, a series of violent riots in western Pennsylvania against the federal liquor tax, according to the National Guard Bureau.

With some exceptions, presidents “avoided calling upon the militia in response to civil disturbances” for most of the 1800s, instead relying on state forces, according to the National Guard Bureau. But it became more common during the civil rights era, when the federal government clashed with officials in Southern, segregationist states. At different times, Presidents Dwight D. Eisenhower, John F. Kennedy and Lyndon B. Johnson federalized the National Guard “to enforce the expansion of civil rights and to ensure public order,” the National Guard Bureau said.

National Guard members were also called in during the “Detroit Rebellion” of 1967 - five days of intense protests over police brutality - as well as the riots that followed Martin Luther King Jr.’s assassination in 1968 and the New York postal strike in 1970.

State officials have a range of tools available to them to deal with civil disturbance, including local, state and federal law enforcement, or even federal troops. They rarely request the National Guard’s assistance - and federal officials doing so is even more uncommon.

The 1992 riots in Los Angeles were the last time the president ordered National Guard troops; Bush did so at the request of California’s Republican governor, Pete Wilson, and the Democratic mayor of Los Angeles, Tom Bradley.

In 2006, President George W. Bush abandoned plans to federalize the Louisiana National Guard in the wake of Hurricane Katrina after the state’s Democratic governor, Kathleen Blanco, opposed it.

Blanco later told a Senate Homeland Security and Governmental Affairs Committee hearing that she believed “that the proper way to do business would be for me, as governor, to retain control of the National Guard and for [Bush] to simply send troops in.”

“There is not a governor in this country, four territories, or the mayor of Washington, D.C., who would give up control of the National Guard,” Blanco said at the time. “You absolutely have to have the law enforcement capacity of the Guard in these circumstances.”

The 1992 Los Angeles riots were also the last time a president invoked the Insurrection Act, which authorizes the president to deploy armed forces or the National Guard domestically to suppress armed rebellion, riots or other extreme circumstances. The Insurrection Act allows U.S. military personnel to perform law enforcement activities - such as making arrests and performing searches - generally prohibited by another law, the Posse Comitatus Act.

Trump has not invoked the Insurrection Act, which means that California National Guard troops can perform logistics and other support missions, but they cannot perform law enforcement operations such as immigration raids, arrests and home searches, Rachel E. VanLandingham, a former Air Force lawyer and a professor at Southwestern Law School in Los Angeles, told The Washington Post.

Speaking to reporters on Sunday, Trump did not rule out invoking the Insurrection Act in response to the Los Angeles protests.

“Depends on whether or not there’s an insurrection,” Trump said in response to a question about whether he was prepared to invoke the law. “We’re not going to let them get away with it.”

According to the Brennan Center for Justice at New York University School of Law, the last time a president invoked the Insurrection Act against a state’s wishes was in 1965, when Johnson federalized the Alabama National Guard troops to protect civil rights activists from violence as they marched from Selma to Montgomery. He did so despite opposition from the state’s Democratic governor, George Wallace, who did not want to use state funds to protect the marchers.

On March 18, 1965, Wallace, who was a segregationist, told the Alabama legislature that he intended to ask for federal troops “to provide for the safety and welfare of the so called demonstrators.” That evening, Johnson addressed the press in his office and said Wallace had “at his disposal over 10,000 trained members of the Alabama National Guard which he could call into service” to protect the marchers and their leader, Martin Luther King.

“If he is unable or unwilling to call up the Guard and to maintain law and order in Alabama, I will call the Guard up and give them all the support that may be required,” Johnson said.

Under the protection of about 1,800 members of the Alabama National Guard and 2,000 soldiers, the marchers walked about 50 miles to the state capitol in Montgomery without any major incidents. That march, along with King’s famous “How Long? Not Long” speech at the end of it, is now viewed as a pivotal moment in the fight for civil rights in the United States.