Some Democrats pole-axed by Joseph Biden’s disastrous debate performance took heart in his relatively rousing appearance at a North Carolina rally the next day. The candidate did everything he wasn’t able to do the night before: speak with energy, deliver punchy one-liners, and, critically, make sense. He also coughed a few times, lending credence to the spin that a cold might have impaired him at the debate. For those seeking any sign at all that the night before was an aberration, North Carolina offered a reed to cling to, no matter how thin. Party leaders seized on it: limited vigor, lapses in acuity—there are good days and bad days and it’s tough to stand at a podium for ninety minutes after a day spent managing multiple global crises; what’s most important is the way he bounced back. Now, more than ever, the party should rally around the president. Democracy itself is at stake, and Biden’s the only one who can protect it, since he’s the only one who can beat Trump.

This last assertion has always been contestable. Within the opening minutes of the debate, it became indefensible. But it didn’t stop the panel on Lawrence O’Donnell’s MSNBC show Friday night from quadrupling down on it. It’s rare that I watch MSNBC, but feeling concerned about the debate myself, I spent much of the next day toggling among streams, screens, and feeds looking for some way to think about what happened and what it might portend for November. “You get back up” was the big line from Biden’s North Carolina rally, and that was the messaging that O’Donnell and guests amplified (it also ran in the segment’s graphics and the chyron at the bottom of the screen). There’s denial, and then there’s what was on display on MSNBC—but not only there, as recipients of Biden-campaign fundraising emails can attest.

Of course, Democrats have been in denial about Biden’s deteriorating condition for a long time. The debate made it obvious that they can no longer afford such complacency. The excuses and explanations and rationalizations in the aftermath only underscore Biden’s unfitness.

True, Trump offered nothing but lies and hate for ninety minutes, and the moderators never challenged him. But Trump always and only deals in lies and hate. The ground rules had made it clear that the hosts wouldn’t call him out, so it was up to Biden to do so. A candidate closer to the top of his game would have challenged Trump directly and corrected the facts himself. It’s not for nothing that many noted the crispness and specificity of Vice President Kamala Harris’s post-debate responses to Trump.

Some defenders of Biden said he’d been over-prepared, armed with information hard to synthesize in a debate. Again, it’s not as if Biden was able marshall even a bit of this data in a coherent manner. He even blanked on what clearly were prepared lines. A more nimble candidate might also have made the in-game pivot to big-picture messaging over policy details.

Some pointed out that Biden was the statesman while Trump was a loudmouth blowhard. Not exactly. Trump managed to clear his own very low bar to seem almost normally behaved, while Biden’s unfortunate slack-jawed, glassy-eyed look made him seem, sadly, a faint shade of his former self—unable to answer questions, unable to respond to his opponent, and unfit to stand for a second term.

Some noted that it was just one debate, with another to come in September, and anyway people have short memories. But this was different from Barack Obama looking peeved and distracted in his first round against Mitt Romney, a precedent some Democrats (including Obama) have cited. It was not a simple gaffe or clumsy misstatement. It was heartbreakingly difficult to watch, for anyone who has a heart, but also impossible to forget. Images from a raucous rally the next day can’t dispel what was plain to all the night before. Age runs in only one direction, and at a faster pace for someone already past eighty. It’s hard to see Biden performing appreciably better months from now, though it’s easy to imagine him doing worse. And then there’s what awaits should he somehow win a second term.

Finally there was the inevitable reminder that Biden’s a fighter, singularly equipped to meet this moment. This gets to another big issue: the hubris that leads a man and those closest to him to believe that he’s the only one who can do what the country needs. Biden did his country a service in defeating Trump in 2020; he risks doing it a disservice now by not standing aside. Insisting that he’s the only option “overlooks the fact that there are other Democrats qualified to run—current governors, senators, and cabinet members—and capable of winning,” as I wrote last September.

Those candidates are still there, in plain sight. Identifying one to step in for Biden isn’t a sign of panic, as some strategists and commentators believe. It’s the assumption of a task the party has too long avoided. That it wasn’t done sooner is unfortunate; to neglect it any longer is political malpractice. What is the purpose of a party if it can’t field a worthy candidate? Worse, if Democrats are serious about Trump’s unique danger to our country in a second term, it would amount to a dereliction of duty. Yes, there are significant technical, logistical, and political hurdles to selecting a new nominee, but they can—and must—be overcome. A new candidate might even make for a welcome new dynamic in our national politics.

By all accounts it is Biden and those closest to him, especially his wife Jill, who would ultimately decide whether he should step away. Many of Biden’s trusted friends in the press have called on him to do so. Many voters, according to polls, feel the same. Biden has accomplished much in a lifetime of public service. But it would be best for the country, and for him, to let someone else serve now.