After winning nearly half the vote in South Carolina’s primary over the weekend, former Vice President Joe Biden tried to frame the race as a two-man contest between himself and Mr. Sanders. The Vermont senator announced on Sunday that he had raised a record $46.5 million in February, giving him a significant financial advantage over all his rivals except Michael Bloomberg.

“The Daily”: Today’s episode is about Mr. Biden’s victory in South Carolina.

What’s next: Fourteen states will vote on Tuesday, perhaps the single most important day on the primary calendar. Mr. Sanders is expected to come out with a substantial lead in delegates. Learn more in our guide to Super Tuesday.

Explainer: The candidates are competing for two major pools of delegates, one allocated statewide and the other by congressional district. A candidate needs at least 15 percent of the vote to be eligible, a rule that’s intended to weed out those without a viable path to the nomination. We explain how it works.

Another angle: In an interview with The Times Magazine, the “West Wing” creator Aaron Sorkin discusses how he’d write the Democratic primary. “There are grand gestures out there to be had, and no one is going for them,” he said. “We’re drowning in timidity.”