When I last spoke to Rick Perlstein, the historian of modern conservatism, Donald Trump had shocked the country by rising to the top of Republican primary polls. He hadn't yet won a single state, however, and the thought of him as the GOP nominee still seemed absurd. Now, with three weeks until the election, Trump's unprecedented candidacy has upended American politics. It has also riven the Republican Party, an organization that Trump ostensibly leads and quite clearly has no use for. Read more