One of the most difficult conversations you can have in life is with a parent or peer who is becoming too old and infirm to work. Whether the infirmity is physical or mental, often your loved one is the last person to realize his own deficiencies, so he may interpret respectful, genuine concern as a personal attack.

This conversation is difficult enough when it’s conducted entirely in private with friends and family. It’s infinitely more difficult when it plays out in public and involves the president of the United States.

The top-line conclusion of special counsel Robert Hur’s report regarding the discovery of classified information at Joe Biden’s home is good for the president. It found, in no uncertain terms, that “no criminal charges are warranted in this matter.” It said prosecution would be inappropriate “even if Department of Justice policy did not foreclose criminal charges against a sitting president.” The report even did the president the favor of clearly and unequivocally distinguishing his treatment of classified materials from Donald Trump’s vastly worse misconduct in his own retention-of-documents case.

But the report presented what may be a worse assessment for Biden than the matter of guilt, which is its description of one reason he won’t be prosecuted: The special counsel found that Biden lacked the requisite degree of criminal willfulness in part because of his fading memory. The report characterized him as a “well-meaning, elderly man with a poor memory” and said he had “diminished faculties in advancing age.” To bolster this assertion, the report provided some damaging details, including claims that Biden couldn’t remember the dates when he was vice president and couldn’t remember “even within several years” when his son Beau died.

The report understandably angered Biden, but in a fiery news conference after the report was released, he confused the president of Egypt with the president of Mexico. In isolation, the gaffe was minor — less serious, for instance, than Trump recently confusing Nikki Haley with Nancy Pelosi — but the timing was terrible. The mistake, coming on the heels of two incidents in recent days in which Biden confused French and German leaders with their deceased predecessors, only served to bolster the special counsel’s conclusions.

Democratic partisans may be furious that the special counsel was so blunt about Biden’s memory. But willfulness and intent are necessary elements of the underlying crimes, so Hur had to explore Biden’s mental state, and include illustrative details.

Witnesses are frequently instructed to say “I don’t remember” when they don’t recall all relevant facts completely and accurately. I’ve taken countless depositions in my career, and “I don’t remember” is one of the most common answers I’ve heard. In such cases, I do not presume this person is incapable of remembering. By including the details of Biden’s memory lapses, however, Hur demonstrated that the president’s responses were well outside the norm. That does not mean that every embarrassing detail in the report was appropriate to include. But including some details was necessary to support its legal conclusions.

Of course, none of this means that Trump is a better candidate for the presidency than Biden. But “better than Trump” is the lowest bar imaginable. Trump is a corrupt and confused 77-year-old who’s facing trial on dozens of felony counts in four separate criminal cases and has recently been found liable for sexual abuse and defamation.

But I can know that Biden would be far better than Trump and still be concerned that he’s not up to the challenge of governing for four more years. “Better than Trump” doesn’t mean that he’d continue to respond to profound foreign and domestic challenges with clarity and energy. “Better than Trump” doesn’t mean we can count on him finishing a second term. “Better than Trump” doesn’t even necessarily mean that he can beat Trump in November.

Compounding the problem for Biden, age is not a challenge that improves with time. It’s likely that Biden’s memory and energy are better now than they’ll be next year, not to mention four years from now. Moreover, millions upon millions of Americans have direct experience with the challenge of advanced age — either as their own minds and bodies ultimately slow down or as they watch it happen to friends and relatives. That same experience makes Americans immune to political spin on the issue. No matter how powerful your rhetoric, you can’t browbeat Americans out of a concern as obvious and relatable as the fact that age matters.

Biden does have a response. He can point to the scoreboard. He has a solid case for reelection given the successes of his first term. I am a conservative, so Biden, while absolutely preferable to Trump, was hardly my first choice for the presidency. But I’ve been mostly impressed by his handling of the conflicts in Ukraine and Israel. We’ve also seen enough legislative compromises during his administration to raise glimmers of hope that Congress can still function on occasion. And the American economy, while hardly perfect, is the envy of the world.

Biden’s record includes its share of missteps, most notably at the border. But he can tell concerned Americans that the best predictor of the next four years is the last four years, and that his verbal slips and stumbles are of little consequence compared with his accomplishments. That’s certainly a fair argument. But Biden has to make it himself, repeatedly and eloquently. The only real answer to the charge that he is in decline is for him to publicly demonstrate that he is not.

If the prospect of Biden making this case fills you with alarm — if you’re concerned that he can’t do so consistently and repeatedly on the campaign trail without triggering a cascade of mistakes and gaffes that compound the problem — then it’s time to ponder a different course of action. Should Biden step aside?

Not only is this suggestion tremendously delicate — as we saw in the news conference Thursday, Biden is now quite angry and defiant — it would also trigger a cascading set of chaotic consequences for the Democratic Party. The party would have to jump-start a primary season, fight through a series of divisive state contests and then coalesce again, all while Trump and the GOP prepare for the general election, raising money and lobbing rhetorical grenades at the divided Democrats.

The Democrats obviously want to avoid such an outcome. But Biden’s polling numbers are grim. Yes, there are good reasons to think that his support might be at a low ebb, and that continued good economic news, combined with continued Republican dysfunction, could be enough to lift him past Trump. But it should be deeply concerning that Biden’s single greatest weakness is the one that he cannot alter: his age.

David French writes for the New York Times.