Why Biden Won South Carolina

Jonathan Bernstein: “The results in Nevada provided the structure for the nomination contest that everyone had been waiting for all along. By finishing second, Biden became the Sanders alternative — and by winning big, Sanders made it necessary for those who didn’t want him to be the nominee to settle for whatever alternative was available. That theory is consistent with the polling, which shows Biden improving immediately after Nevada. If it’s correct, then we can think of Clyburn’s endorsement as an effect of Nevada as much as it may have been a cause of what happened in South Carolina.”

“This is consistent with reporting from on-the-trail journalists such as the Washington Post’s David Weigel. It’s also consistent with what the political science literature says about most voters in primaries: They often don’t focus on the contest until right at the end, and they don’t really want to consider all of the candidates who have been running — they just want some signal about which ones are the serious contenders.”