The two men spoke at least a half dozen times before Mr. Biden decided to run, and Mr. Obama took pains to cast his doubts about the campaign in personal terms.
“You don’t have to do this, Joe, you really don’t,” Mr. Obama told Mr. Biden earlier this year, according to a person familiar with the exchange.
Mr. Biden — who thinks he could have defeated Donald Trump four years ago — responded by telling Mr. Obama he could never forgive himself if he turned down a second shot at Mr. Trump.
Mr. Obama has said he will not make an endorsement in the primary, and has offered every candidate his counsel. But he has taken an active interest in the inner workings of his friend’s campaign, to an extent beyond anything offered to other candidates.
When they were done, Mr. Obama offered a pointed reminder, according to two people with knowledge of his comments:
Win or lose, they needed to make sure Mr. Biden did not “embarrass himself” or “damage his legacy” during the campaign.
