CBS News debate moderators on what's at stake in South Carolina
"CBS This Morning" co-host Gayle King and "CBS Evening News" anchor and managing editor Norah O'Donnell will co-moderate Tuesday night's Democratic debate in South Carolina. They'll be joined in questioning by "60 Minutes" correspondent Bill Whitaker, chief Washington correspondent Major Garrett and "Face the Nation" moderator and senior foreign affairs correspondent Margaret Brennan. The five of them break down what's on the line for the candidates.