For Voters, When Does Old Become Too Old?

When a reporter asked President Biden on Thursday night about concerns about his age, his first instinct was to reject the premise. He replied in part: “That is your judgment. That is not the judgment of the press.”

The question was about the public’s concern, not the press, but either way the concerns over his age were not just those of one reporter.

A clear majority of Americans harbor serious doubts about it, polls show. To take just one example: In Times/Siena polling last fall, more than 70 percent of battleground state voters agreed with the statement that Mr. Biden’s “just too old to be an effective president.” More than 60 percent said they didn’t think Mr. Biden had “the mental sharpness to be an effective president.” And fair or not, fewer than half of voters express similar doubts about Donald J. Trump’s age or mental acuity.

Of all the reasons Mr. Biden has narrowly trailed Mr. Trump in the polls for five straight months, this is arguably the single most straightforward explanation. It’s what voters are telling pollsters, whether in open-ended questioning about Mr. Biden or when specifically asked about his age, and they say it in overwhelming numbers. In Times/Siena polling, even a majority of Mr. Biden’s own supporters say he’s too old to be an effective president. His political problems might just be that simple.

Now, just because it’s easy to blame Mr. Biden’s age for his political woes doesn’t make it so. There’s no doubt that voters have concerns, but it’s very hard to figure out how much support it’s costing Mr. Biden in the polls. We can’t know, for instance, what his approval rating would be if he were 10 or 20 years younger. Maybe it would be nearly as low, because of the border, the Middle East, earlier inflation, lingering resentments and anxieties after the pandemic — alongside the corroding effects of partisan polarization.

Why can’t we know? The age issue is not like the economy, in which easily measurable data helps us make sense of its import. We know 10 percent inflation or 10 percent unemployment could be sufficient to cost a president re-election. We’ve seen it before, based on decades of hard data. In contrast, the severity of Mr. Biden’s age problem is almost entirely up for debate. That perception is mostly subjective — based on how he appears and sounds, not simply based on the fact of his being 81. (Mr. Trump is 77.)