It’s never a good thing for a president to trip and fall during a reelection campaign. When the president is already 80 and there are concerns about his ability to serve another term, this can be a crisis.

Joe Biden’s aides realized that they had a serious problem when, last month, the president tripped on a sandbag at the Air Force Academy’s graduation ceremony. Two people who were present at the post-event discussion said that a few aides spent some time trying to determine what went wrong, and how they could ensure such an embarrassing, dangerous, and potentially fatal incident would never happen again.

One person said, “You cannot be too careful.”

Polls show that Biden’s response to voters who doubt whether he can handle a second term was simple: “Watch Me.” But the voters were watching and their impressions about him hardened, making them believe it was time to move on. The presidency is not only the most demanding job in the world, but it’s also the most visible. Signs of ageing are hard to miss.

Anyone paying attention will notice that Biden is not the same man he was in 1987 during the Robert Bork Supreme Court Confirmation Hearings or 2008 at the Vice Presidential Debate with Sarah Palin. His speech is not as fluid, nor is his gait. He has confused Rolling Fork with Mississippi and Rolling Fork with Ukraine.

One congressional Democrat who spoke on condition of anonymity in order to speak freely about the president’s fitness said: “The Democratic Party must be responsive to what people say about Biden and to their concerns about his age.” The number of texts I received after the president fell was overwhelming. My phone was exploding. “Oh, this is terrible!” People say.

Biden’s advisors, aware of the unbending truth that no one ever gets younger, have tried to minimize concerns about his age during his 2020 campaign. As the oldest president ever embarks on his final race, the challenge becomes more difficult. The Republican Party is eager to capitalize on any misstep.

When voters already believe that Biden is a candidate who should retire, any misstep will be amplified. Biden’s aides don’t promise that he will not stumble again.

“Physically he is quite frail, and he falls of his bicycle or whatever,” said an ex-Western diplomat, who spoke under condition of anonymity in order to speak more freely. “He does not have the stamina of an Obama or younger president.” Many worry about Biden’s physical frailty, and the fact that he would be 86 years old at the end of his second term. “That’s really old according to European standards. It’s really, really old. “We don’t have anyone of that age.”

Biden’s advisors seem to be taking steps in order to reduce the physical strain of the job, while also ramping up their two-pronged strategy to turn a weakness electorally into a strength. They argue that Republicans are simply recycling an argument made by the now 77 year old Donald Trump during the 2020 presidential campaign and failed to resonate with voters.

It’s difficult to ignore the fact that Republican officials have been complaining about President Biden’s age since early 2019.

The White House appears to be making concessions in order to show voters what they can expect if Biden is re-elected and continues to serve into his 80s. The modern president is often pictured waving as he walks up the steps to Air Force One. Biden is increasingly choosing the shorter staircase that leads him through the plane’s stomach over the longer one. This type of workaround is not new. John F. Kennedy was 43 when he became the youngest president in history. He suffered from chronic back pain, and was photographed using a cherry picker to lift him onto Air Force One.

According to an analysis conducted by NBC News, Biden has used the shorter staircase more than twice as much since his tumble during the commencement ceremony. This, of course reduces the chance of a televised, viral fall. Biden used shorter stairs 37% of time to board and exit the presidential plane in the weeks before tripping. In the last seven weeks, he has used the stairs 84% of time or 31 of 37 times that he has gotten on and out of the plane.

Biden, who was on a quick trip to Philadelphia for a speech about the economy, used the lower set of stairs at Joint Base Andrews to board the President’s plane. He used the larger staircase to leave the plane when he first arrived in Philadelphia. But a few hours after that, he used the smaller steps.

The White House didn’t directly answer the question of whether Biden used the shorter staircase in order to reduce the risk of falling. The choice is based on weather, airport and whether or not the press wants to take a picture with the official greeters. There was no rain on Thursday when Biden chose the shorter staircase at Joint Base Andrews.

Biden appears to be conserving his energy in another way. On foreign trips, it’s common for the presidents to mingle with other leaders after the meetings. The dinners are less formal and structured than events that precede them. They offer leaders a chance to talk about differences, or to amplify their point. Biden chose to avoid the evening socializing on two recent trips abroad.

He didn’t show up for a dinner at the NATO summit earlier this month in Lithuania. His aides explained that he had been abroad for four days and was preparing to give a speech and attend meetings the following day. He did not attend a dinner in Bali with his counterparts last fall.

When asked about his absence, White House staffers said that it had nothing to with fatigue. Biden, they said, must attend to domestic matters even while he’s overseas. They cited his ability to coordinate a united allied response at night, when it seemed a Russian missile had struck Poland, as proof he was not drained from his travels.

Jonathan Finer is a White House deputy national security advisor. He said, “The dinners are always a good time.”