The following article by Greg Wright was posted on the Conversation website September 5, 2017:
President Donald Trump tweeted on September 3 that the U.S. “is considering, in addition to other options, stopping all trade with any country doing business with North Korea” after it performed a nuclear test.
Though North Korea currently trades with nearly 100 countries, this threat was almost certainly aimed at China, by far its biggest trading partner.
And it is technically something that a U.S. president can do. Under the International Emergency Economic Powers Act of 1977, the president can impose trade restrictions in the face of an “unusual and extraordinary threat.”