Trump wants to send troops to the inner cities. A top senator wants to rein him in.

A top Democratic senator is renewing his effort to rein in Donald Trump’s — or any other future president’s — authority to deploy the military inside the U.S., following recent threats from the former commander in chief to use troops to tamp down violence in cities if reelected.

Sen. Richard Blumenthal (D-Conn.), a senior member of the Homeland, Armed Services and Judiciary committees, told POLITICO he is seeking Republicans and Democrats to join his latest effort to overhaul the law involving deployments inside the U.S., known as the Insurrection Act.

The law, enacted in 1792, grants the president the authority to deploy the military domestically and use it against Americans to suppress rebellion or violence. But Blumenthal and other critics argue that it is overly broad and ripe for abuse.

“Ideally, there would be interest on the Republican side because the potential for abuse really ought to concern all of us, regardless of who was president,” Blumenthal said.

Trump's back-to-back wins in Iowa and New Hampshire have tightened his grip on the Republican Party’s presidential nomination, prompting worried lawmakers and foreign governments to devise plans to prepare for and protect against more upheaval.

The renewed push comes after Trump told an Iowa audience that he considered, but held back from, deploying the military to inner cities to fight crime. He also called New York City and Chicago “crime dens.”

“And one of the other things I’ll do — because you’re supposed to not be involved in that — you just have to be asked by the governor or the mayor to come in. The next time, I’m not waiting,” Trump said in November. “One of the things I did was let them run it, and we’re going to show how bad a job they do. Well, we did that. We don’t have to wait any longer.”

Blumenthal tried to sharpen the law once before in 2020, following Trump’s threats to use troops amid civil rights protests across the U.S. following the police killing of George Floyd. At the time, progressive Reps. Pramila Jayapal (D-Wash.), Mark Pocan (D-Wis.) and Ilhan Omar (D-Minn.), introduced a companion bill, which attracted 25 cosponsors but never made it onto the House floor. In 2020, the Democratic-controlled House added a modified version to the annual defense policy bill, but the Republican-controlled Senate and the final bill did not.

Whether Democrats in the House will revive their push alongside Blumenthal this time is unclear, but the measure would have better chances in the Democratic-controlled Senate than in the Republican-controlled House.

Blumenthal said he is drafting a new version of his legislation that would amend the law to more clearly define what an insurrection is and the circumstances under which the president can use force, though he did not offer specifics. It would also grant local officials standing in the courts to have the emergency lifted at some point after the act is invoked.

Under the law now, a president may deploy troops to “suppress rebellion” whenever “unlawful obstructions, combinations, or assemblages, or rebellion” make it “impracticable” to enforce federal law in that state by the “ordinary course of judicial proceedings.”

It also allows a president to send the military to suppress “any insurrection, domestic violence, unlawful combination, or conspiracy” in a state that “opposes or obstructs the execution of the laws of the United States or impedes the course of justice under those laws.” Presidents Dwight D. Eisenhower and John F. Kennedy relied on that language to enforce the Brown v. Board of Education desegregation case.

This isn’t the only legislation coming ahead of a potential Trump presidency that appears designed to rein him in. As part of the fiscal 2024 Pentagon policy bill, Congress approved bipartisan legislation that would prevent any president from withdrawing the United States from NATO without approval from the Senate or an act of Congress.

The measure, from Sens. Tim Kaine (D-Va.) and Marco Rubio (R-Fla.), protects an alliance that was a frequent target for Trump. The former president has reportedly been discussing the possibility of withdrawing the U.S. from NATO, if elected.

Blumenthal said he hopes to introduce the proposed changes to the Insurrection Act in the coming weeks as a stand-alone bill. At some point, he could attempt to add it to the next annual Pentagon policy bill.

“President Trump has in fact talked about sending troops into cities where he regards the police as being inadequate — in effect, potentially declaring martial law,” Blumenthal said, “so I think there needs to be stronger oversight.”

“I think part of the evidence for enacting reform is in fact Donald Trump’s own statements about how he would abuse the insurrection powers,” Blumenthal added.

Amid the 2020 protests, Trump threatened to use the military to stamp out the unrest across the country. Soon after, Defense Secretary Mark Esper publicly broke with Trump and said he did not support invoking the Insurrection Act — and issued an internal memo urging the department’s workers to “stay apolitical in these turbulent days."

Esper later said in his memoir that he and now-retired Gen. Mark Milley, who was then the Joint Chiefs chair, talked Trump out of deploying the military to quell protests outside the White House over Floyd’s killing.

Blumenthal said that relying on the military, which is supposed to stay out of politics, to be a bulwark against a rogue president would be inappropriate. Congress needs to step in now, he argued.

“It is essentially protecting the military against improper political interference,” he said of his legislation.

“I think to put the burden on the military for avoiding misuse of the insurrection powers of the presidency is an unfair burden on them,” he added. “They’re professionals, they’re charged to protect the country. They should not be making decisions about whether it's proper to put the National Guard in Chicago to stop fentanyl trading.”

Blumenthal stressed that his proposal is not “anti-Trump” and would apply to any president, an acknowledgment that any potential Republican supporters might be subject to political pressure if the measure is seen as targeting the former president. But Trump is clearly on his mind.

“There's no guarantee that a Democrat or Republican will be in the White House, but there is clearly the bipartisan danger of abuse of the Insurrection Act just because it is so vaguely worded,” he added.

Blumenthal said he is working on the legislation with legal scholars at the nonpartisan Brennan Center for Justice in New York.

“There’s a lot of interest on the Democratic side, and there’s some interest on the Republican side,” he said.

“This is not new,” he added. “People in the academic world have complained for some time that this ambiguity and potential for abuse is in the statute. Nobody really thought that it was an imminent danger until now.”