 President Biden's campaign is working to ensure that delegates won by Mr. Biden vote for him at the August convention. CBS's Major Garrett explains convention rules do not bind delegates to a candidate, but do require them to reflect in good conscience the outcome of the state's primary or caucus. He has the delegates. He's won the primaries. He's won the caucuses. And unless he decides to step aside, it will be very difficult to get those delegates to defect.