From left, Democratic presidential candidates, former New York City Mayor Mike Bloomberg, former South Bend Mayor Pete Buttigieg, Sen. Elizabeth Warren, D-Mass., and Sen. Bernie Sanders, I-Vt., 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/Patrick Semansky)