This week Chad P. Bown and Soumaya Keynes focus on the South Korea-US free trade agreement (KORUS) and President Donald Trump’s unhappiness with it, as his administration alternates between threats of withdrawal and renegotiation. The episode chronicles the rocky negotiating history of the deal, explains the role of professional economists in advising trade policymakers, and evaluates the performance of KORUS five years after it was finally implemented.