Republican leaders in Congress say they have no objections to President Trump invoking the Insurrection Act of 1807 should he choose to do so. Mr. Trump said Tuesday that he may use his executive power to invoke the statute in order to expand the military presence at Los Angeles in response to the riots there. 

Both Senator Thune and Speaker Johnson said Tuesday that it is up to the president if he wanted to take such a step. Unrest in the city, kicked off over the weekend by protesters demonstrating against ICE’s deportation operations, has only grown worse in recent days, with looting of retail stores downtown and significant violence aimed at police. 

“That is the president’s decision and it’s not a decision of Congress, so I gotta leave that to him,” Mr. Johnson tells the Sun. 

Mr. Thune said Tuesday that the law was signed in 1807 “for a reason.” The majority leader says that if Governor Newsom and the city’s mayor, Karen Bass, fail to protect their citizens, then the president is within his rights to take extraordinary measures.

The last time the Insurrection Act was invoked was in 1992 — also at Los Angeles — during the Rodney King riots, also by a Republican president, George H.W. Bush, but at the request of the state’s governor at the time, Republican Pete Wilson, instead of over the objections of one. 

“I think it’s there for a reason. If there is a public safety issue and the local officials aren’t getting anything done …,” he said, trailing off as he walked on to the Senate floor for a vote. 

On Tuesday, Senator Cotton published an opinion article in the Wall Street Journal saying he supports a potential move to invoke the Insurrection Act if necessary. The op-ed comes almost five years to the day after Mr. Cotton authored a similar piece for the New York Times that called on the president to use the military to put down the 2020 riots. Publication of the article led the newspaper to dismiss several of its top editors after Black employees called it racist and said it endangered their lives.

“If the Guard alone can’t restore order and protect federal officers and property, the president can use active-duty troops under the Insurrection Act of 1807, a law almost as old as the republic,” Mr. Cotton writes. “Let’s hope that the National Guard, federal law enforcement and local police can end the anarchy and restore order to Los Angeles.”

Earlier in the day, the president himself said that “if” he believed there was an insurrection in California, then he would “certainly” take that step to invoke the 1807 law. “We’ll see,” the president told reporters in the Oval Office. “I can tell you, last night was terrible. The night before that was terrible.”

“I could tell you, there were certain areas of Los Angeles last night — you could’ve called it an insurrection. It was terrible,” Mr. Trump added. “These are paid insurrectionists. These are paid troublemakers. … They hurt some people very badly.”

Mr. Trump has already invoked emergency powers to federalize and deploy the California National Guard as part of his attempt to quell the protests. 

The executive order signed by the president on Saturday states that the forces will be used to “temporarily protect ICE and other United States Government personnel who are performing Federal functions, including the enforcement of Federal law, and to protect Federal property, at locations where protests against these functions are occurring or are likely to occur based on current threat assessments and planned operations.”

The section of the United States Code that Mr. Trump is invoking only states that the president may federalize the National Guard for security purposes if a state is “invaded or is in danger of invasion by a foreign nation,” “there is a rebellion or danger of a rebellion against the authority of the Government of the United States,” or if “the President is unable with the regular forces to execute the laws of the United States.”

That statute further states that the guard may only be called up at the president’s direction “through the governors of the States.” California is already suing to block Mr. Trump’s executive order, arguing that the president is exceeding his presidential authority because he did not receive permission from Governor Newsom to mobilize the California National Guard. 

“The Constitution reserves to the States power over their respective state militias — now the National Guard — unless the State requests or consents to federal control. Only under the most exigent of circumstances can the President, over the objections of a State, call the National Guard into federal service,” California’s attorney general, Rob Bonta, wrote in his lawsuit. 

Democratic members of Congress from California denounced the possible use of the Insurrection Act to dispel protesters at a press conference Tuesday. Speaker Pelosi, who joined the press event, wondered aloud why Mr. Trump would activate the National Guard in California now, even when he did not do so on January 6, 2021. 

“With violence against the Constitution, against the Congress, and against the United States Capitol, we begged the President of the United States to send in the National Guard. He would not do it,” Ms. Pelosi said. “And yet, in a contra-constitutional way, he has sent the National Guard into California. Something is very wrong with this picture.”