On the campaign trail, candidate Donald Trump promised to toughen up our trade relationship with China. And now, after an exchange of import tariffs, many economists fear we may be on the way to a trade war. Princeton economics professor Alan S. Blinder joins us to talk about how politicians often fail to fully consider the economic impact of their decisions, which he writes about in “Advice and Dissent: Why America Suffers When Economics and Politics Collide” (Basic Books).