Keynes and Bown compare President Donald Trump’s tariffs imposed to date—on solar panels, washing machines, steel, aluminum, and Chinese imports—with other major American protectionist episodes. They speak to economic historian Douglas A. Irwin (PIIE) about the Reagan administration’s protectionism in the 1980s, the 1971 Nixon shock, the 1960s US-Europe chicken war, and the 1930 Smoot-Hawley tariff.