The Democratic presidential race has entered a phase that is specifically designed to reward front-runners and push out lesser-known candidates. We look at how that will influence the campaign. Guest: Alexander Burns, who covers national politics for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.  Background coverage: Which candidates are leading the Democratic primary? Here’s a look at the state of the race.Listen to an episode of “The Daily” about the intended and unintended consequences of the Democratic National Committee’s new debate qualifying rules.