Those presidential powers can be used “to deal with any unusual and extraordinary threat….to the national security, foreign policy, or economy of the United States.”
Under the IEEPA, the President has to consult with Congress before invoking his authority and, after declaring a national emergency, send a report to Congress explaining why.
This authority has been used frequently; there have been 54 national emergencies, 29 of which are ongoing. In the first use of the IEEPA, during the Iran hostage crisis in 1979, President Jimmy Carter imposed trade sanctions against Iran, freezing Iranian assets in the US, according to CRS.
Stephen Vladeck, a law professor at the University of Texas and a CNN legal analyst, told CNN in May that what Trump wanted to do under the law with Mexico may have been within the authority given to the White House by Congress — though it might not have been what Congress ever intended.
“The idea behind these authorities is that the President is better situated to make those kinds of determinations than Congress, especially when they’re time-sensitive,” Vladeck told CNN at the time. “So I think the President’s conduct may well be within the letter of the law here. But, as with the National Emergencies Act, I very much doubt this kind of exercise of the authority conferred by the statute is what Congress had in mind.”
On Saturday, Vladeck again weighed in, tweeting: “One of the enduring phenomena of the Trump era is going to be the list of statutes that give far too much power to the President, but that many didn’t used to worry about—assuming there’d be political safeguards. Today’s entrant: The International Emergency Economic Powers Act.”
Under the law, though, Congress can end an emergency with a joint resolution.
Former Massachusetts Gov. Bill Weld, who has mounted a longshot bid against Trump for the 2020 Republican presidential nomination, called it “outrageous” that a US President would tell US companies how to conduct business.
CNN’s Zachary B. Wolf and Nikki Carvajal contributed to this report.