In announcing his retirement last month, Utah senator Mitt Romney called on the two likely major-party presidential nominees to step down as well. “I think it would be a great thing if both President Biden and former President Trump were to stand aside and let their respective party pick someone in the next generation…. I think both parties would be far better served if they were going to be represented by people other than those of us from the baby-boom generation.” He was unintentionally generous regarding Biden, born too early to be a boomer (1942), but his point was well taken—even if, as a fitting capstone to his politically moderate senatorial career, it will likely have zero impact.

Biden once hinted at doing exactly what Romney has proposed, positioning himself during the 2020 primaries as a transitional figure bridging the Democratic Party’s past and its future. He was then seventy-seven, already older than the oldest-ever incoming president: Donald Trump, inaugurated at seventy. Voters otherwise averse to Biden might have heard this as a pledge to serve a single term—or at least to seriously consider it—and so voted for him with the single aim of defeating Trump. That done, the party could turn to its bench for a 2024 nominee, perhaps someone more demonstrably attuned to progressive sensibilities about climate, immigration, and the economy, and, by default, someone younger.     

Biden, as we know now, seems to have had a longer bridge in mind. With incumbency comes the privilege of acting as the presumptive nominee, and the party establishment has coalesced around him. In normal circumstances this would be perfectly fine, especially given Biden’s restoration of stability and civility and the policy achievements he can lay claim to. But these are not normal circumstances. Biden’s approval rating is terrible; he polls poorly against Trump and other GOP candidates; and the majority of Democratic voters don’t want him to run. All of these can be traced in some degree to one thing: Biden’s age.

It may seem ageist or unkind. But Americans should be forgiven their hesitancy in returning someone who will be eighty-two years old to the nation’s highest office. The vast majority of people over seventy-five are retired, and with good reason: growing older makes it harder to work. It also makes it harder to stay healthy. Research shows the chance of acquiring three diseases simultaneously rises ten-fold between the ages of seventy and eighty, then ten-fold again in the next decade of life. Millions of Americans have experienced these and other effects of aging themselves, and millions more have watched elderly loved ones go through them. Add to that the unique stressors of the presidency, which seem to age presidents before our eyes, and the concerns over Biden’s age become impossible to dismiss. Clips of him cycling in Delaware do little to distract from clear signs of diminished physical vigor and verbal acuity.

Biden and those around him insist he’s fit to run and that he is Democrats’ best option. Their certainty rests on two contestable assumptions. One is that Trump will be the GOP nominee. But legal troubles and his own age-related health issues could change that, and it’s not all that hard to imagine how, say, a Nikki Haley would fare against Biden. The other assumption is that if Trump is the nominee, only Biden could beat him. That overestimates Trump and Biden both, and blithely overlooks the fact that there are other Democrats qualified to run—current governors, senators, and cabinet members—and capable of winning. If the party believes that Biden is truly the only option, then it could be on a bridge to nowhere.