Conservatives slam Donald Trump's tariffs as unconstitutional. Also, tourism from nations hit by Trump's tariffs plummets. Plus, while leaving his White House role Elon Musk dodged a question about a New York Times reports on his alleged drug use on the campaign trail. And Trump pardons criminals convicted of tax and fraud crimes. Jared Bernstein, Nevada Attorney General Aaron Ford, Ruth Ben-Ghiat, and Brendan Ballou join Ali Velshi.