Editor’s note: This column was written before the announcement that former President Joe Biden is suffering from advanced prostate cancer.

In 2022, after I wrote a column arguing that Joe Biden was too old to run for reelection, I had a bunch of conversations and at least one cable TV debate with Democrats who thought I was wrong.

Officials and pundits I spoke to seemed convinced that it would be crazy for the party to give up the advantages of incumbency, that a primary risked creating nasty fissures among various Democratic factions, and, most relevantly, that Biden’s legislative successes proved he was still up to the job.

For many people, Republicans especially, the Democratic Party’s ongoing insistence that Biden was basically fine looks like a fraud committed against the electorate.

In “Original Sin,” Jake Tapper and Alex Thompson’s explosive new book about Biden’s deterioration, they call the widespread refusal to admit how bad he had become a “cover-up.”

There was certainly some covering up going on, especially among Biden’s insular inner circle. But more than lying to the public about Biden’s increasing infirmity, I think too many Democrats were lying to themselves.

The “original sin” that party leaders now need to grapple with is their tendency toward groupthink, inertia and an extreme and wildly counterproductive risk aversion.

Plenty of Democrats are annoyed that “Original Sin” has catapulted the issue of Biden’s enfeeblement back into the news, threatening to distract voters from Donald Trump’s rococo corruption.

I think, though, that Tapper and Thompson have done the party a favor. Some sort of reckoning is due for the disastrous missteps that paved the way for Trump’s return. Party officials burned a lot of credibility defending Biden’s cognitive fitness.

Politically, the easiest move for Democrats is to dump all the blame onto Biden, his family and the clique of longtime aides Tapper and Thompson call “the Politburo:” Mike Donilon, Steve Ricchetti and Bruce Reed.

This group certainly deserves to be excoriated; Tapper and Thompson marshal lots of evidence that Biden was even worse behind the scenes than in public and those closest to the president tightly restricted access to him to obscure the problem.

They quote a senior White House aide who left because he or she didn’t want to see Biden run again: “We attempted to shield him from his own staff so many people didn’t realize the extent of the decline.”

But while his closest associates might have hidden the worst of erosion, it was plain enough to anyone willing to see it.

Again and again, voters told pollsters that the president was too old to run for reelection. If ordinary people recognized the problem, why couldn’t the insiders?

One reason may be that gerontocracy is increasingly the norm in American politics. More than a dozen senators are 75 or older; one, Iowa’s Chuck Grassley, is in his 90s.

“Covering for an aging politician is commonplace in modern Washington,” write Tapper and Thompson, who quote Nikki Haley calling the Senate “the most privileged nursing home in the country.”

Tapper and Thompson, it’s important to note, don’t report that Biden’s addled state led to poor judgment, at least aside from the catastrophic choice to run for reelection.

Indeed, they wrote, Biden critics they spoke to “continued to the end to attest to his ability to make sound decisions, if on his own schedule.”

Had Biden been younger, Tapper and Thompson suggest, he might have been more forceful on the border. But on a day-to-day basis, the administration often looked, to those who shared its priorities, to be doing a decent job.

According to “Original Sin,” Biden was confident that Trump would self-destruct on the debate stage and all he had to do was stand back and let him. Reading that, I thought of the strategists who argued that after Trump’s reelection, Democrats should “roll over and play dead,” in James Carville’s words, while Republicans discredit themselves.

There might still have been time after Biden’s calamitous June debate performance to put together a mini-primary, or at least a process of democratic consultation, to choose a replacement. (That, Tapper and Thompson write, is what Barack Obama and Nancy Pelosi wanted to do.)

Creating such a process would have required the party to quickly come to terms with the scale of the emergency they faced, to realize that the ordinary rules of politics needed to be tossed aside.

Instead, even after Democrats realized Biden’s campaign couldn’t continue, the party faced nearly a month of indecision.

Less than a week after the debate, write Tapper and Thompson, the House party caucus chair, Pete Aguilar, understood that “the overwhelming majority of House Democrats wanted Biden to step down, but most were keeping quiet out of respect.”

They needed less deference and more courage. They still do.

Michelle Goldberg is a New York Times columnist.