But at the same news conference — about 12 minutes long — after discussing the current state of the Israel-Gaza war, Biden referred to President Abdel Fatah El-Sisi, the leader of Egypt, as the president of Mexico. That followed a week in which Biden described contacts he’d had as president with former German chancellor Helmut Kohl, who died in 2017, and former French president Francois Mitterrand, who died in 1996.

The president’s aides and allies then went on a blitz to showcase people who had vouched for the president’s fitness, including former Republican House Speaker Kevin McCarthy, while dismissing Hur as an overstepping tool of Donald Trump — a point echoed by some legal experts. White House press secretary Karine Jean-Pierre in a daily briefing read off a list of instances in which Republicans mixed up names or government programs, arguing that such moments are normal for politicians of all ages.

It was a tactic — attack, belittle and counter — that has been repeated again and again through Biden’s term. When questions about his age and ability to serve another four-year term have surfaced — whether from the news media, lawmakers or the general public — the president’s aides have been quick to deny any problem. They have argued the president — who has said questions about his age are fair — has remained sharp as ever and maintained an aggressive campaign and foreign travel schedule, with presidential days running for 12 hours or longer.

They said that reporters focused only on the president’s age and not on that of Trump, who is 78, arguing Biden was held to an unfair standard. And they said his long legislative record speaks for itself — even as poll after poll showed that voters were deeply concerned about the issue.

Now, after his halting performance at a debate against Trump brought questions of Biden’s mental sharpness and physical stamina to the forefront, Biden’s senior aides face worries among fellow Democrats and sharp accusations from Republicans that they took steps to conceal the effect the president’s aging has had on his ability to carry out his duties.

Aides have increasingly shielded Biden from unscripted encounters — shortening his interactions with the news media and installing teleprompters at virtually all of his appearances where he would give remarks, even small private events — sparking suspicion among those who interact with him less often that his aging and decline may be worse than aides have acknowledged. White House officials say that Biden still works rope lines, holds informal gatherings with reporters and holds unscripted policy meetings with key stakeholders. Biden now wears tennis shoes and uses shorter stairs to Air Force One, to lessen the chances he might trip. First lady Jill Biden sometimes stands ready to help him on or off a stage, and aides often provide him with note cards to remind him of points to make in meetings.

But Republicans are already accusing Biden and the White House of engaging in a coverup, signaling they would use Democrats’ handling of Biden’s aging not only against him but also against Vice President Harris should she replace him at the top of the ticket. In a statement last week, Trump campaign chiefs Chris LaCivita and Susie Wiles said Democrats, the news media and “the swamp” had “colluded to hide the truth from the American public.”

“Every one of them has lied about Joe Biden’s cognitive state and supported his disastrous policies over the past four years, especially Cackling Copilot Kamala Harris,” they added.

Even some Democratic allies have said they believe the White House failed to address the president’s aging with transparency and candor, allowing it to fester while the party lost key months in the effort to vanquish Trump, who they believe is a potentially existential threat to democracy.

“What we need right now — and what I think takes a spine — is to step aside and recognize the president of the United States doesn’t have the vigor necessary to overcome the deficit here and it’s going to affect us all,” Rep. Mike Quigley (D-Il.) said Friday on CNN.

Current and former senior administration officials, lawmakers, donors and members of the Democratic National Committee said any discussion about the president’s vitality — and signs that his aging has accelerated in recent months — have been too politically risky to have in public, and too uncomfortable in private, even with fellow Democrats.

They largely did not question Biden’s mental acuity, but instead said the president has appeared slower in recent months and has had more frequent lapses in meetings, including briefly losing his train of thought before getting back on track. Some of those lapses have occurred during public events, moments Republicans seize on and blast on social media, often by omitting critical context.

“I definitely brought it up with people like, is anyone else concerned here? There were very quiet conversations in the building,” one former White House official recalled. “It’s almost like a no-go zone. You’d be worried to bring it up in a conversation with people you can’t trust.”

The White House has added a number of events to Biden’s schedule in the coming days to address those concerns and demonstrate the president’s fitness, including media interviews, campaign stops and a solo news conference next week. During an interview with ABC News on Friday, Biden defied growing calls from sitting Democrats to exit the race. “If the Lord Almighty said get out of the race, I’d get out of the race,” Biden said. “The Lord Almighty’s not coming down.”

He also swatted away concerns about his health and age, calling the debate “a bad night” and saying doctors have told him there is no need for him to undergo cognitive testing.

“Can I run the 100 in 10 flat? No,” he said. “But I’m still in good shape.”

White House aides have long echoed those attitudes, strongly refuting the idea that Biden’s age is a problem, insisting that he remains mentally undiminished and that any physical slowing does not affect his ability to serve as president. When asked about the issue, they quickly line up advisers to vouch for Biden’s behind-the-scenes acuity. Since the debate, aides in interviews have said Biden continues to ask probing, tough questions in briefings and speech preparation and argue he has deftly managed numerous international crises, including Russia’s invasion of Ukraine and Israel’s war in Gaza.

As for Biden’s public speaking — when he has occasionally slurred his words, trailed off mid-speech or confused names and facts — they have noted Biden has long been a gaffe-prone politician who has not been known as an especially strong public speaker and contends with a lifelong stutter.

Trump, they have countered, has rambled incoherently at several recent events. They argue that any concerns about Biden’s faculties pale in comparison to the litany of liabilities Trump has, including a felony conviction and multiple pending legal cases, and the threat they say he poses to democracy.

The Biden campaign pointed to numerous times it said Trump has lied while in office and while campaigning — including about the 2020 election, covid and crime — arguing voters would choose Biden — an old man who they say will uphold democracy — over Trump.

“That’s what the choice for voters will be this November — between Trump, a wannabe dictator fighting for himself, and Joe Biden who cares about fighting to make people’s lives better,” Ammar Moussa, a Biden campaign spokesman, said in a statement Saturday.

But quiet concerns in the Democratic Party have become more pronounced since the debate. Biden has relied on a small circle of senior aides throughout his first term, prompting complaints from donors, lawmakers and longtime friends and allies as early as Biden’s first year in office that they lacked access to the president. White House aides countered that many people wanted more of the president’s limited time and dismissed it as the usual complaining that exists with any administration.

That close-hold approach in many ways stemmed from the fact that the final months of Biden’s presidential campaign came during the height of the coronavirus pandemic — a time when he was mostly confined to his Wilmington, Del., basement as medical experts advised sheltering in place to avoid contracting the deadly virus.

Covid remained an acute threat throughout most of Biden’s first year in office, and aides took extensive steps to ensure the president, who was at high risk of a complicated covid infection because of his advanced age, did not get infected. During that time, only a small number of aides were given regular access to the president and therefore gained significant power, according to people familiar with the protocol. That approach has persisted throughout Biden’s first term, even as the threat from covid eased. A White House official, who spoke on the condition of anonymity to discuss internal protocol, said Biden interacts with various aides on myriad policy issues.

“As he has built the most successful record in modern American history, standing up for middle class families against recession-causing MAGAnomics and bringing violent crime to a 50-year low, Joe Biden has always said that it is fair for reporters to ask about his age and has always confidently put his values and agenda to the American people,” White House spokesman Andrew Bates said in a statement.

Biden was dogged by questions about his age from the start, when at 77 years old in 2020 he vied to become the oldest president in history. Once in office, he has also long struggled with how to talk about his age. Jeffrey Katzenberg, a Biden campaign co-chair, urged aides to lean into the issue and argue that with Biden’s more than 80 years comes wisdom and experience — an approach some Democratic lawmakers have also advocated.

“Joe Biden’s age is his superpower, and as I’ve seen firsthand, his fastball is as good as ever,” Katzenberg told NBC a year ago.

But Biden himself was defensive. His initial answer to anyone who asked whether he was up for another term was to “watch me.” As polls showed the president’s age was growing into a top voter concern, Biden began to make light of the issue by joking about it. At the State of the Union in March, Biden said, “I know I may not look like it, but I’ve been around a while,” then went on to add the issue facing the country “isn’t how old we are, it’s how old our ideas are.”