An Associated Press-NORC survey released late last month indicated that 77% of adults in the U.S. believe Biden is too old to be effective for another term. That includes 69% of Democrats.

A Wall Street Journal survey yielded similar results, plus this stinging finding: Only 36% of voters said they consider Biden “mentally up for the job.”

“You can see, even from the beginning of his presidency until now, there’s definitely been some decline — and that’s worrisome,” a Pennsylvania Democrat named Elena said in a focus group for “PBS NewsHour” last month. (Voters participated on the condition that their full identities would not be disclosed.)

Sarah Longwell, the anti-Trump Republican strategist who conducted the session, said Democratic voters raise the issue of Biden’s age without being prompted.

“Age is the first thing they talk about,” she said.

“I was a little surprised at how down on Biden they were,” she added. “We asked them to give him a letter grade, and most were in the low Bs and Cs.”

At this early stage in a presidential campaign, poll numbers should be taken with a grain of salt, especially those that purport to forecast an election that’s 14 months away.

But the bipartisan doubts about Biden are too lopsided to dismiss.

It may seem unfair that many voters consider Biden too old at 80, but give former President Trump something of a pass at 77. In the Wall Street Journal poll, 46% said they considered Trump mentally fit for the presidency — better than Biden, but still less than impressive.

One explanation may be that Trump presents an image of manic vigor, while Biden sometimes appears hesitant and fragile.

“Even though he’s a bully, [Trump] doesn’t falter, he doesn’t mumble, he doesn’t fall off the steps,” another Democrat in the focus group said. “Biden does.”

Peel back the voters’ views, though, and it’s not just Biden’s stiff gait or sometimes-jumbled speech that’s at issue.

Voters’ core concern remains the economy, on which most give the president low marks.

In the AP-NORC poll, only 36% of respondents said they approve of Biden’s economic leadership. That includes 65% of Democrats — a relatively low showing among the president’s base.

At first glance, those numbers seem paradoxical. The economy is growing at a healthy clip, unemployment is low, and inflation, which peaked last year at 9%, has slowed to about 4%.

But in interviews and focus groups, voters don’t cite the overall rate of inflation; they complain about the stubbornly high price of housing, groceries and gasoline.

“Voters aren’t feeling the benefits of the economy,” Longwell said. “They think Biden is too old, and they don’t think he’s doing a good job.”

Despite voters’ qualms, it doesn’t appear that any leading Democrat will challenge the president for the nomination — and there’s no sign that Biden has considered stepping down.

A new book on his presidency, “The Last Politician” by Franklin Foer of the Atlantic magazine, describes Biden as confident that he can win again.

Foer writes that Biden’s 53-year political career has taught him a lesson: “Just after he is dismissed as past his prime … he pulls off his greatest successes.”

What the president wants most is to “prove the establishment naysayers wrong,” Foer concluded.

Biden did that in 2020, when he won the Democratic nomination and defeated Trump, and again in 2022, when he led Democrats to unexpectedly good results in the midterm election.

Can he do it again in 2024, when he’ll be just shy of 82 on election day?

He’s already made a start.

After initially ducking questions about his age — “It doesn’t register with me,” he claimed this spring — he quickly turned to joking about it.

“You say I’m ancient? I say I’m wise,” he said just days later.

His staff has quietly taken steps to protect his health. They are more careful to make sure there are no obstacles in his path, like the sandbag he tripped over at the Air Force Academy in June.

His schedule is a little lighter, with fewer evening events — a step Ronald Reagan also took as a president in his 70s.

But Biden still relishes his role as diplomat in chief, and he seems intent on proving he has the stamina for it. Last week he set out on a grueling round-the-world trip with stops in India and Vietnam, jammed into just four days.

But his foreign travel won’t assuage voters’ main concerns.

There are two factors that could still help Biden win a second term.

One is the economy: Inflation appears to be ebbing. By next year, if prices level off, more voters might give Biden credit for the recovery.

The other is the likely nomination of Trump, whose standing in the polls is almost equally low.

When Longwell asked the Democrats in her focus group how they would vote if their choice came down to Biden or Trump, almost every hand shot up for Biden.

“If Trump is the nominee, they’ll get more enthusiastic,” she said. “Not necessarily for Biden, but to keep Trump away from the presidency.”

Biden can’t make voters forget that he’s 80 years old and counting. But he may be able to change the subject and prove the naysayers wrong one last time.