What Joe Biden wants to accomplish at the virtual DNC

As Democrats begin the first night of their virtual 2020 convention, "CBS Evening News" anchor and managing editor Norah O'Donnell previews what former Vice President Joe Biden is looking to accomplish. O'Donnell spoke to "60 Minutes" correspondent John Dickerson and CBS News political contributors María Elena Salinas and Jamal Simmons about what the presumptive nominee needs to do to help his chances in November.