The 3rd Democratic Presidential Debate: What You Should Watch For On Thursday night ten Democratic candidates will face off. It's the first time former Vice President Joe Biden will face Senators Bernie Sanders and Elizabeth Warren. Plus, Trump faces a new challenger in the Republican field. This episode: White House correspondent Tamara Keith, political correspondent Scott Detrow, and national political correspondent Mara Liasson. Email the show at email@example.com. Find and support your local public radio station at npr.org/stations.