DETROIT — Two days after President Biden’s disastrous debate performance, the buzz started among Michigan Democrats: Why doesn’t he step aside in favor of Gretchen Whitmer?

Michigan’s two-term governor is, after all, young (53 in August) charismatic, a proven vote-getter and clearly ambitious. Her just-published biography, True Gretch: What I’ve Learned About Life, Leadership and Everything In Between (Simon and Schuster, $26.99) reads like a campaign biography.

Many in the national media, including some conservatives like the New York Times’ Bret Stephens, have been touting her for years.  So what are the chances of her replacing the President?

Truthfully, just about zero.

Actually, the governor knows that very well, as much as she almost certainly would like to be President tomorrow.

When a column in Politico alleged that she had told the Biden campaign that the President could no longer win Michigan, she responded by saying, “Not only do I believe Joe Biden can win Michigan, I know he can.  I am proud to support Joe Biden as our nominee, and I am behind him 100 percent.”

How true is that? We cannot really know. But what we do know is that President Biden, should he ever decide not to run, would have no more ability than you or I to designate a nominee.

What would happen is that nearly two thousand delegates who are now pledged to Biden would be free agents, and at least half a dozen candidates, likely more, would be fighting for their votes.

In fact, there’s only one way Joseph Robinette Biden can choose the next President of the United States, and he would have only one choice. He could resign in favor of Vice President Kamala Harris.

Should he do that, she would, as the incumbent, almost certainly be the favorite to be nominated when the Democratic National Convention begins in Chicago on Aug. 19. 

There’s also no doubt that the President doesn’t want to drop out of the race. But let’s imagine he suddenly decides not to run, but announces he will finish his term, which is what Lyndon Johnson did at the end of March 1968.

That would set off a mad scramble for the nomination. Gretchen Whitmer might well run, but so would other Democrats, including Vice-President Harris, and probably California Gov. Gavin Newsom, U.S. Sens. Cory Booker of New Jersey, Amy Klobuchar of Minnesota, and who knows how many others?

          That would likely mean something no one has seen since 1952– a convention that took more than one ballot to nominate a presidential candidate. It’s been so long that most people have forgotten how that would work.

Under both parties’ rules, to win the nomination, it wouldn’t be enough to have more delegate votes than anyone else. Winning the nomination takes a majority, and it might be hard for anyone to corral more than half the delegates in just a few days or weeks.

Conventions that took multiple ballots used to happen all the time, before the 1960s, when presidential primaries became first the main, then almost the only way of selecting delegates. That was especially true when an incumbent president wasn’t running.

For example, it took six roll calls to nominate Abraham Lincoln, and four to select Franklin D. Roosevelt. What went on between ballots was frantic horse trading, in which candidates often agreed to drop out in return for the vice-presidency or some other job.

Sometimes, that worked very well, and led to the strongest candidate being nominated. However, it broke down completely exactly a century ago, when a deadlocked Democratic National Convention took two weeks and 103 ballots to confer what by then was a worthless presidential nomination on an unknown dark horse.

What would Gretchen Whitmer’s chances be if there was suddenly a wide-open convention? That’s difficult to say, though it is possible that as a young but experienced politician who is perceived as both compelling and moderate, she could do very well.

But even if she were to win the nomination, she’d have another big problem.  Many Black Democrats, especially women, feel that if President Biden doesn’t run, Kamala Harris has earned the right to succeed him, and they are not going to be happy if she isn’t the nominee.  That doesn’t mean they will vote for Donald Trump, but they may not vote at all. And no Democrat can win a national election without a huge and enthusiastic African American turnout.

Trump would also be able to say that while 16.9 million people voted for him in the primaries, not a single vote was cast for Whitmer, who he would say was nominated in back room deals.

Precedents are sometimes broken, however, and the pundits never thought Donald Trump could get elected president, much less that skinny Black guy with the African-sounding name.

Stranger things have happened, but not many. But it’s a fair bet that we will see a few more this year.  After all, this campaign still has more than three and a half months to go.

(Editor’s Note: A version of this column also appeared in the Toledo Blade