He just doesn't get it. And neither do those closest to him.
Asked by George Stephanopoulos how he would feel if he loses, he told the truth and it was the wrong answer. "I'll feel as long as I gave it my all and I did the good as job as I know I can do, that's what this is about."
No, it's not. What this is about is not Joe Biden doing "the good as job as I know I can do."
No one doubts that Joe Biden will do his best. This is about saving our democracy. Biden himself has said that.
It is the most important election in our lifetime. President Donald Trump, if you listen to his agenda, is no Ronald Reagan, no George H.W. Bush or George W. Bush, no Mitt Romney or John McCain.
He poses risks and is more radical and less presidential than any of those candidates. He has no interest in uniting this country. He has promised to get even with his opponents.
He will take a divided country and divide it further. He will remake the Supreme Court in his image for a generation to come. And it will be Joe Biden's fault.
Joe Biden says he will not let 90 minutes undo three and a half years of successful work. That is not the issue either. No one is taking the achievements of the last three and a half years away from him.
The people who are turning on him now are people who supported him for the last four years — in many cases, more — and were prepared to support him going forward. They are turning on him not because of one bad night but because they are worried that the man who stumbled and stammered on that stage is not up to the job he is running for, and that he is going to lose.
And it's getting worse, not better. If Biden were trying to prove he's up to the challenges of being president, why did he need his staff to write the questions for the two interviews on the radio he did after the debate as part of his failed effort to rehabilitate himself? One of those interviewers has already lost their job, rightly so.
What does it prove that you can answer questions that your staff wrote — and no doubt prepared you for? And he still bungled the softballs. They were clearly afraid to let Joe be Joe, so used to doing that, that they did it even when the only point of the exercise was to showcase the man's ability without a script or a teleprompter.
What that episode revealed is what the press has finally begun reporting: that, as a stunner of an article in New York Magazine reported, there has been a kind of unholy "conspiracy" among Biden's staff and the press who follow him, to hide his decline from us. They have not served him, or us, well.
We should have known that the press corps joked about what percent "dead" he seemed when he encountered people he's known for years and didn't recognize them except with a glassy stare.
The conspiracy is over. Biden is under a microscope, his every stumble is going to be covered, and it's not going to be pretty.
He is losing his fundraising advantage, and it is going to get worse. Key donors have already said publicly that they have shut off the spigot. What they are saying publicly is merely the tip of a melting iceberg.
Biden says he doesn't care what the millionaires think, but he has relied on those millionaires to build his diminishing war chest. He is not the grassroots fundraising machine that his opponent is.
There has not been an outpouring of financial support for him since June 27's disaster the way there was for Donald Trump after his conviction. Trump is going to outraise and outspend him.
Biden says that if someone wants to run against him, they should challenge him at the convention. That's no answer. Ninety-nine percent of the delegates to the convention (and the only ones who can vote on the first ballot) are pledged to support Biden. They were picked by his campaign.
The roll call this year is scheduled to be held virtually, so he will be nominated before anyone even arrives in Chicago. That proves nothing.
Biden says he's always been the underdog, that he's been knocked down before and always gotten up and showed them. Not so. At this point in 2020, he was nine points ahead of Donald Trump.
As CNN's chief pollster pointed out, Kamala Harris does better among independents than he does. He's right that he's been knocked down before, most notably by my friends in 1987, but he didn't get up and win; he got out of the race, which was the right move.
But Joe Biden is convinced that even if the chattering class that used to support him has turned against him, he's going to win.
I'm sure he believes that. It's because he's living in a bubble, where people tell him what he wants to hear and where the crowds in middle school gyms greet him with cheers.
I'm an expert in losing campaigns. I've heard people tell me what they really think and then pull their punches with the candidate.
And did you hear those crowds cheer, the candidates say, cheering crowds being the penicillin for losing candidates to keep going. The worse the campaign is going, the harder the advance people work to produce a cheering crowd. It means nothing.
What Biden needs, and what he deserves, is straight talk and the honest truth from people who know how to win elections, from elected officials and party leaders and seasoned strategists who are saying to each other what his family is never going to say to him.
He did well. But the party's over, and it is time to step aside.
Susan Estrich is a politician, professor, lawyer and writer. She has appeared on the pages of The New York Times, the Los Angeles Times, and The Washington Post. Ms. Estrich has also appeared as a television commentator on CNN, Fox News, NBC, ABC, CBS, and NBC. Her focus is on legal matters, women's concerns, national politics, and social issues. Read Susan Estrich's Reports — More Here.