Saturday was Joe Biden’s first-ever win in a presidential primary or caucus. It was an awfully big one: Biden won South Carolina by nearly 30 percentage points over Bernie Sanders. And it made for one heck of a comeback: Biden’s lead over Sanders had fallen to as little as 2 to 3 percentage points in our South Carolina polling average in the immediate aftermath of New Hampshire.
What explains the big swing back to Biden in South Carolina? And what does it mean for the rest of the race — and in particular for Sanders, who had entered this weekend as the frontrunner?
Here are five possible explanations — ranging from the most benign for Sanders to the most troubling for his campaign. CONT.
Nate Silver, FiveThirtyEight