"I called on Mr. Biden to step aside almost a year ago, warning that he would be forever known as 'Ruth Bader Biden' if he didn’t."

"Since then, each time I would bring up that idea, publicly or privately, people would dismiss it out of hand: Get on board, they’d say, the Democrats will never replace him, it’s off the table.  Well, now it’s on the table, where it always should have been. And far from being some kind of disaster for the Democratic Party, it plays right into what works best in 21-century American culture. Americans like new.... Democrats could not buy, with all of George Soros’s money, the enthusiasm, engagement and interest they would get from having an open convention — and in Chicago no less, famous for Democratic convention drama. Suddenly, instead of rehashing the debate from hell — worst episode of 'The Golden Bachelor' ever — they would be hosting a competition, something Americans love. Who will get the rose this August in Chicago? Gavin or Gretchen? Suddenly, Stacey Abrams might say she’s in! And so might Tim Ryan, and Josh Shapiro! And Amy Klobuchar and Ruben Gallego! And Mayor Pete and Raphael Warnock! And Wes Moore, and who knows, maybe Andrew Yang says he’s a Democrat again!... My pick would be Gavin Newsom.... "

Writes Bill Maher, in "Why I Want an Open Convention" (NYT).

Maher, a comedian, claims not to be joking, but how can there be an open convention when the Democrats announced a plan to nominate Biden through a virtual convention that would take place in time to meet Ohio's ballot-access requirement?

But that's not the only reason to balk at a chaotic convention. Bandying about all those names of people who did not subject themselves to any of the debates and primaries that voters think of as a democratic process?

But let's look at the rules —"What happens if a presidential candidate cannot take office due to death or incapacitation...?" (Brookings):

The Democratic National Committee (DNC) is also authorized to select the party’s nominee in the event that the winner of the convention cannot run. This is spelled out in the charter of the Democrat Party.... 

This has actually happened only once before. After the 1972 convention, revelations came out that George McGovern’s running mate Sen. Tom Eagleton, had been treated for mental illness. Eagleton was forced to resign from the ticket and McGovern chose Sargent Shriver as his replacement. But McGovern alone could not place Shriver on the ticket with him, it needed to be ratified by the full DNC. And so, on August 9, 1972, the DNC chair, Jean Westwood, called the national committee into session to officially nominate Shriver as McGovern’s running mate. 

The authority of the national parties to choose their nominee in the event the nominee can’t run comes as a surprise to many in this day of wall-to-wall primaries. And yet, it is a reminder that the choice of a nominee is party business — not state law, not federal law, and not constitutional law....

I think the plan should be — must be — that the virtual convention will take place and nominate Biden, and after that, the DNC will choose its candidate. Will that happen before or after the formal convention? I suspect the DNC will use the formal convention to display the candidates, including the DNC's choice, and just tell us who that is later.