Polls drive a lot of political news. To talk about why, how they work, and what might be wrong with them, Nate Cohn, who writes for The Upshot at the New York Times, joins host Tamara Keith and digital political reporter Danielle Kurtzleben. Find them on Twitter @tamarakeithNPR, @titonka, @Nate_Cohn, or at npr.org/politics.