Who Is Leading In The 2020 Presidential Race?

Former Vice President Joe Biden has called for President Trump's impeachment for the first time. Sen. Elizabeth Warren defends her explanation that she was pushed out of a teaching job for being pregnant. And Sen. Bernie Sanders says he'll continue a vigorous campaign after suffering a minor heart attack.

We check in on the state of the 2020 Democratic primary contest with NPR political correspondent Scott Detrow (@scottdetrow).