With the perspective of time, though, perhaps Obama’s decision not to push his party to accept an heir apparent of his choice was a mistake. Without the long shadow of a president who was and remains very popular among Democrats, the Donkey Party endured a bitter primary fight in 2016 that in turn contributed to an infinitely regrettable general-election defeat. And now Democrats are dealing with the largest presidential field in the history of American politics, with an arguably shaky soon-to-be-octogenarian front-runner who would not even be in the race if not for his Obama connection.

Putting aside the original running-mate decision in 2008 on grounds that candidate Obama had bigger fish to fry and had no intention of guaranteeing Joe Biden a ticket to the White House, should Obama have reconsidered this decision in 2012 and gone ahead and designated an heir apparent for real? By then he and his people probably knew that even if they thought Biden would be too old to run in 2016 (or later), he sure didn’t. And they could have saved Democrats a world of grief by eliminating a serious primary battle in 2016 and in 2020.

The identity of a 2012 Biden substitute, of course, could have been problematic. The obvious replacement would have been then-secretary of State Hillary Clinton, a choice that would have made history. But if Obama recognized the need to turn the page on the Clinton legacy that he had himself done a lot to relegate to the history books in 2008, he might have chosen a younger and less controversial running mate — perhaps even one who could have helped him in that tough 2012 general election more than Joe Biden did.