WASHINGTON – Widespread concerns about United States President Joe Biden’s age pose a deepening threat to his re-election bid, with a majority of voters who supported him in 2020 now saying he is too old to lead the country effectively, according to a new poll by The New York Times and Siena College.

The survey pointed to a fundamental shift in how voters who backed Mr Biden four years ago have come to see him.

A striking 61 per cent said they thought he was “just too old” to be an effective president.

A sizeable share was even more worried – 19 per cent of those who voted for Mr Biden in 2020, and 13 per cent of those who said they would back him in November, said the 81-year-old President’s age was such a problem that he was no longer capable of handling the job.

The misgivings about Mr Biden’s age cut across generations, gender, race and education, underscoring the President’s failure to dispel both concerns within his own party and Republican attacks painting him as senile.

Seventy-three per cent of all registered voters said he was too old to be effective, and 45 per cent expressed a belief that he could not do the job.

This unease, which has long surfaced in polls and in quiet conversations with Democratic officials, appears to be growing as Mr Biden moves towards formally capturing his party’s nomination.

The poll was conducted more than two weeks after scrutiny of his age intensified in early February, when a special counsel described him in a report as a “well-meaning, elderly man with a poor memory” and “diminished faculties in advancing age.”

Previous polling suggests that voters’ reservations about Mr Biden’s age have grown over time.

In six top battleground states surveyed in October, 55 per cent of those who voted for him in 2020 said they believed he was too old to be an effective president, a sharp increase from the 16 per cent of Democrats who shared that concern in a slightly different set of swing states in 2020.

Voters have not expressed the same anxieties about Donald Trump, who at 77 is just four years Mr Biden’s junior. Their likely rematch would make them the oldest presidential nominees in history.

If re-elected, Mr Biden would beat his own record as the oldest sitting president, while Trump would be the second-oldest if he won. Trump would be 82 at the end of the term, and Mr Biden would be 86.

In the most recent Times survey, 19 per cent of all voters said Trump’s age was such a problem that he was not capable of handling the presidency.

And in a sign of Republicans’ far greater confidence in their likely nominee, less than 1 per cent of voters who backed Trump in 2020 said his age made him incapable.

Mr Biden and his allies have rejected anxieties about his age and mental acuity as unfair and inaccurate.

His campaign says its coalition will again rally around the President once it fully recognises that Trump could win back the White House. It also argues that Mr Biden faced age concerns in 2020 and still won.

Yet Mr Biden is now four years older, and it may be impossible to completely reassure voters about his age given the inexorable march of time.

The poll indicates that the worries about him are not only pernicious, but also now intertwined with how many voters view him.

Mr Calvin Nurjadin, a Democrat in Cedar Park, Texas, who plans to support Mr Biden in November, said he was unconvinced by politicians in his party who have publicly played up their direct observations of Mr Biden’s mental sharpness.

“You’ve just kind of seen the clips of, you know, he’s having memories onstage and, you know, during debate and discussion where he kind of freezes up a lot,” said Mr Nurjadin, who does data entry work. “Him being sharp and fit is not very convincing.”

Even though the country is bitterly divided and Republican voters have overwhelmingly negative views of Mr Biden’s age, Democrats do not appear to be more worried about the effects of time on Trump than on Mr Biden. Similar shares of Democrats said each man was too old to be effective.

The poll tried to understand in greater depth how voters thought about Mr Biden’s and Trump’s abilities.

The survey first asked if each man was too old to be effective. Voters who said yes were asked a follow-up question about whether that age was such a problem that Mr Biden or Trump was not capable of handling the job, a stronger measure that prompted voters to consider the candidate’s basic fitness for office.

Mr Shermaine Elmore, 44, a small-business owner in Baltimore, voted for Mr Biden four years ago, backing the Democratic candidate as he had in previous elections.

But he said he had made more money under Trump, blaming inflation and gas prices for his losses during the Biden administration. He planned to vote for Trump this fall.

Of Mr Biden, he said: “I don’t think he’s in the best health to make a decision if the country needs the president to make a decision.”

The New York Times/Siena College poll of 980 registered voters nationwide was conducted on cellular and landline telephones, using live interviewers, from Feb 25-28.

The margin of sampling error for the presidential ballot choice question is plus or minus 3.5 percentage points among registered voters. NYTIMES