Just over a week ago, Bernie Sanders seemed to be the front-runner for the Democratic nomination. Then came some prominent withdrawals from the race, and, on Super Tuesday, the resurgence of Joe Biden’s campaign. (Tulsi Gabbard of Hawaii remains in the race, but has no chance of winning the nomination.) But the narrowing of the field only highlights the gulf between the Party’s moderate center and its energized Left.  David Remnick talks with Amy Davidson Sorkin, a political columnist for The New Yorker, about the possibility of a contested Convention. Then Remnick interviews Michael Kazin, an historian and the co-editor of Dissent magazine. Kazin points out that Sanders is struggling against a headwind: even voters sympathetic to democratic socialism may vote for a pragmatist if they think Biden is more likely to beat the incumbent President in November. But Sanders seems unlikely to moderate his message. “There is a problem,” Kazin tells David Remnick. “A divided party—a party that’s divided at the Convention—never has won in American politics.”