The results of Super Tuesday make clear that the race for the Democratic presidential nomination is increasingly a battle between former Vice President Joseph R. Biden Jr. and Senator Bernie Sanders. Today, we explore what happened on the biggest night of the race so far. Guest: Alexander Burns, who covers national politics for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily. Background reading: Mr. Biden is back as front-runner after sweeping states across the south thanks to moderates and African-American voters, while Mr. Sanders harnessed the backing of liberals and young voters to claim California, the biggest delegate prize of the night.Primary results are still coming in. Here are the latest updates and The Times’s live analysis.