Calling it "a great thing to do," President Trump declared a national emergency on Friday in order to help finance a long-promised wall on the U.S.-Mexico border. It's a highly unusual move from an unconventional president. This episode: political reporter Asma Khalid, White House correspondent Tamara Keith, and Congressional correspondent Susan Davis. Email the show at nprpolitics@npr.org. Find and support your local public radio station at npr.org/stations.