“Bolton’s bombshell.”

John Bolton’s explosive new book upends Donald Trump’s impeachment trial, Adam Schiff joins to talk about what happens next, and Bernie Sanders extends his lead in Iowa as other candidates raise electability questions. Then Ezra Klein talks to Dan about his new book, “Why We’re Polarized.” Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.