SCPM362; From left, Democratic presidential candidates, Sen. Bernie Sanders, I-Vt., former Vice President Joe Biden, and Sen. Amy Klobuchar, D-Minn., participate in a Democratic presidential primary debate at the Gaillard Center, Tuesday, Feb. 25, 2020, in Charleston, S.C., co-hosted by CBS News and the Congressional Black Caucus Institute. (AP Photo) AP / LEHTIKUVA / PATRICK SEMANSKY