Anderson Cooper 360

Campaign Aides: Biden Plans To Take On Warren At Debate Tonight; He's Been Reading Her Proposals, Could Raise Questions About Them; Campaign Aide: Biden Will Target Warren, Argue "It's Not Just About Plans; It's About Getting Things Done For People"; Adviser: Harris Will Argue "Longing For The Past" And "Ideological Fights" Won't Bring The Country Together; House Judiciary Democrat Talks Impeachment Investigation; Who's Most Capable Of Taking On Pres. Trump?; Axelrod's Message To Dems: "Let Trump Destroy Trump; Business Leaders Sign Letter Demanding Action On Gun Violence; 145 Business Leaders Call On Sense To Pass "Common-Sense, Bipartisan" Gun Laws; House Judiciary approves Rules Defining Impeachment Investigation; House Judiciary Approves Inquiry Parameters As Democrats Try To Clarify Their Strategy; New Tropical Threat For The Bahamas; Tropical Storm Warning In Effect For Part Of Bahamas; 1,3000 People Now Listed As Missing On Isla