Anderson Cooper 360

Round Two: High Stakes And A Heavyweight for CNN Debate; What to Look For Tonight's Candidates; What To Look For From Tonight's Candidates; Candidates Arrive At Debate Hall; Rematch Between Biden And Harris At Centerstage Tonight; Top Harris Campaign Aide Previews Debate Night; Will Sen. harris Take On Former VP Joe Biden Tonight?; Fight For The Soul Of The Democratic Party; The Flint City Wide Choir & Dee Dee Bridgewater Sing "America The Beautiful" At CNN Democratic Debate; Biden Campaign Official: "No Rules Of Engagement" At Debate via Knit