Oct. 7, 2025, 5:17 PM EDTBy Gary Grumbach and Dareh GregorianPresident Donald Trump suggested numerous times this week that he could invoke the sweeping presidential powers granted by the Insurrection Act “if necessary.””It’s been invoked before,” Trump told reporters Tuesday, adding, “We want safe cities.”Using the Insurrection Act was something Trump repeatedly suggested he might do in his first term, although he never actually did.A spokeswoman for the White House, Abigail Jackson, said in a statement Tuesday that the president has “exercised his lawful authority to protect federal officers and assets. President Trump will not turn a blind eye to the lawlessness plaguing American cities.”Here’s a look at what the Insurrection Act is, and what it would enable the president to do.What is the Insurrection Act?While the military is generally barred from being deployed for domestic law enforcement without congressional authorization, the Insurrection Act gives the president power to deploy the U.S. military domestically and to federalize National Guard troops during specific circumstances.It was signed into law by President Thomas Jefferson in March 1807.Has it ever been used before?Many times, but not in decades.George Washington used an earlier version of the law to stamp out the Whiskey Rebellion in 1792.President George H.W. Bush was the last to use it during the deadly 1992 Los Angeles riots, following a request from the city’s Democratic mayor and the state’s Republican governor.What can trigger the use of the Insurrection Act?While one justification for invoking the act is clear — that the president can take action if asked to do so by a governor or a Legislature — the other standards mentioned in the statute are broad and vague, giving the president wide latitude.“Whenever the President considers that unlawful obstructions, combinations, or assemblages, or rebellion against the authority of the United States, make it impracticable to enforce the laws of the United States in any State by the ordinary course of judicial proceedings, he may call into Federal service such of the militia of any State, and use such of the armed forces, as he considers necessary to enforce those laws or to suppress the rebellion,” the statute reads.Another section says the president, “by using the militia or the armed forces, or both,” shall “take such measures as he considers necessary to suppress, in a State, any insurrection, domestic violence, unlawful combination, or conspiracy” if it “hinders the execution of the laws of that State, and of the United States within the State,” or if it “opposes or obstructs the execution of the laws of the United States or impedes the course of justice under those laws.”The statutes don’t define the terms, essentially leaving it up to the president to determine what constitutes an insurrection or rebellion, and when it’s been quelled.A 2022 review from the Brennan Center, a progressive policy group, called that provision “so bafflingly broad that it cannot possibly mean what it says, or else it authorizes the president to use the military against any two people conspiring to break federal law.”How does Trump define insurrection?The president — who was impeached on a charge of inciting insurrection on Jan. 6, 2021 — has indicated he has a low bar for what he considers insurrection, but has also said he doesn’t believe the criteria to use the act have been met.Trump mentioned the word insurrection — which the Encyclopaedia Britannica defines as “an organized and usually violent act of revolt or rebellion against an established government or governing authority” — five times on Monday.”Portland is on fire. Portland’s been on fire for years. And not so much saving it — we have to save something else, because I think that‘s all insurrection, really criminal insurrection,” Trump said at one point in the Oval Office on Monday. He told Newsmax later in the day that the situation in Portland was “pure insurrection.”Earlier in the day, he said he’d invoke the act “if it was necessary. So far it hasn’t been necessary but we have an Insurrection Act for a reason. If I had to enact it, I’d do that. If people were being killed and courts were holding us up, or governors or mayors were holding us up, sure I’d do that. I want to make sure that people aren’t killed.”Speaking to reporters on Tuesday, he broadened his definition, saying “these Democrats are like insurrectionists” because they opposed his “big beautiful bill.”How would using the Insurrection Act be different from what Trump is already doing?The Insurrection Act gives the military more freedom to perform law enforcement duties, such as conducting searches and making arrests.When Trump deployed the National Guard and the Marines in Los Angeles amid protests over his immigration policies, they were publicly assigned a more limited role, focused on protecting federal buildings and activities.A federal judge in California last month found they actually did more than that, and violated the Posse Comitatus Act of 1878, which prohibits the president from using the military as a domestic police force without approval from Congress or under special circumstances — such as an invocation of the Insurrection Act.“The evidence at trial established that Defendants systematically used armed soldiers (whose identity was often obscured by protective armor) and military vehicles to set up protective perimeters and traffic blockades, engage in crowd control, and otherwise demonstrate a military presence in and around Los Angeles,” U.S. District Judge Charles Breyer wrote in his ruling.“In short, Defendants violated the Posse Comitatus Act,” he said.The administration is appealing the ruling and an appeals court has put the ruling on hold while the case proceeds.Gary GrumbachGary Grumbach is an NBC News legal affairs reporter, based in Washington, D.C.Dareh GregorianDareh Gregorian is a politics reporter for NBC News.Tara Prindiville contributed.