Callie Crossley, host of WGBH News’ Under The Radar, joined Boston Public Radio on Friday to speak about why Black Democratic voters in Southern states turned out to support former Vice President Joe Biden on Super Tuesday.

"So much has happened in terms of racial progress, and if there is any threat to that — because there is — here are people living with the history itself and they are not about to have that return to the past," Crossley said. "There's James Blyburn's wonderful endorsement of 'Joe knows us,' and so they decided to place their bets on Joe Biden."