On the campaign trail, Donald Trump and Kamala Harris are constantly talking about trade, tariffs and domestic manufacturing.In many ways, these talking points stem from a single trade deal that transformed the U.S. economy and remade both parties’ relationship with the working class.Dan Kaufman, a contributing writer for The New York Times Magazine, explains how the North American Free Trade Agreement broke American politics.Guest: Dan Kaufman, the author of “The Fall of Wisconsin,” and a contributing writer for The New York Times Magazine.Background reading: