U.S. presidential campaigns have a way of echoing throughout history. Take this year: a race with two deeply unpopular candidates, a spotlight on one candidate’s private correspondence and inflammatory comments made by another. These may be headlines in 2016, but similar stories are in the history books, too. On the other hand, some moments from past primaries, conventions and debates feel utterly unique. John Dickerson, moderator of “Face the Nation,” has spent decades covering elections, and he documents his favorite stories from campaign history in a new book called “Whistlestop.” He joins us to share some of his favorite tales from the campaign trail… and to talk about what moments from the 2016 race future historians might look back on.