After a series of troubling moments this week, an uncomfortable question has become unavoidable, leaving voters, strategists and even politicians themselves wondering: Just how old is too old to serve in public office?

For years, like so many children of aging parents across America, politicians and their advisers in Washington tried to skirt that difficult conversation, wrapping concerns about their octogenarian leaders in a cone of silence. The omertà was enabled by the traditions of a city that arms public figures with a battalion of aides, who manage nearly all of their professional and personal lives.

“I don’t know what the magic number is, but I do think that as a general rule, my goodness, when you get into the 80s, it’s time to think about a little relaxation,” said Trent Lott, 81, a former Senate majority leader who retired at the spry age of 67 to start his own lobbying firm. “The problem is, you get elected to a six-year term, you’re in pretty good shape, but four years later you may not be so good.”

Two closely scrutinized episodes this week thrust questions about aging with dignity in public office out of the halls of Congress and into the national conversation.

On Wednesday, video of Senator Mitch McConnell, 81, freezing for 20 seconds in front of television cameras reverberated across the internet and newscasts. Less than 24 hours later, another clip surfaced of Senator Dianne Feinstein, 90, appearing confused when asked to vote in committee.

A political discussion on the issue of age has been building for months, as the country faces the possibility of a presidential contest between the oldest candidates in American history. President Biden, 80, already the oldest president to sit in the White House, is vying for a second term, and Donald J. Trump, 77, is leading the Republican primary race.

“When I say we need to pass the baton to younger generations, I’m not talking about youthful generations,” said Representative Dean Phillips of Minnesota, 54, the only Democrat in Congress to say that Ms. Feinstein should step down and that Mr. Biden should not seek re-election. “I’m talking about simply a reasonably less aged generation.”

Mr. McConnell’s stumble created a fresh opening for younger contenders to raise the issue more aggressively. On Friday, Gov. Ron DeSantis of Florida, 44, a top Republican presidential candidate, took a jab at the country’s political gerontocracy.

“You used to serve in your prime and then pass the baton to the next generation, and I think this generation has not really been as willing to do that,” Mr. DeSantis told the conservative commentator Megyn Kelly, noting that Mr. Biden became a senator in 1973 — five years before Mr. DeSantis was born.

Notably, Mr. Trump, who would be 82 at the end of a second term, has defended Mr. Biden, saying that the president should not be discounted because of his age. “He is not an old man,” Mr. Trump posted this month on Truth Social, his social media platform. “In actuality, life begins at 80!”

Doctors for Mr. Biden have said he is in good health. Less is known about Mr. Trump’s health since he left the White House.

After Mr. Biden was captured tripping over a sandbag in June, White House aides have grown increasingly sensitive to any insinuation that he is physically diminished.

He now regularly uses a shorter set of stairs to board Air Force One, an observation noted in a report by Politico that prompted aides to circulate 13 photos of his predecessors using stairs that appear to be of a similar length. He has not gone out to get his beloved ice cream, or dropped into any other business for an impromptu visit with voters, since early May.

Some top advisers to Mr. Biden argue that his campaign should directly embrace his age as a political asset — and undeniable reality — rather than avoid the issue.

“Age is in fact a superpower,” said Jeffrey Katzenberg, 72, the Hollywood mogul whom Mr. Biden named as a co-chairman of his campaign. “You can’t run from it because you’re 80 years old, right? There’s no denying it. I’ve been of the camp that believes strongly this is one of his greatest assets.”

Surveys indicate that voters disagree, with many Democratic voters worrying about Mr. Biden’s age amid Republican attacks. In polling conducted by YouGov last year, a majority of Americans supported age limits for elected officials but were split over the precise cutoff. A cap at age 60 would bar 71 percent of the Senate from holding office, while a limit of 70 would render 30 percent ineligible, an analysis by the firm found.

In North Dakota, a conservative activist this week began circulating petitions to force a statewide referendum next year that would prohibit anyone who would turn 81 by the end of their term from being elected or appointed to congressional seats.

When asked, Mr. Biden dismisses worries about his age with jokes and boasts about his political experience. Mr. McConnell took a similar approach, telling reporters that he joked with the president about his health scare by saying that he had been “sandbagged” — a reference to how Mr. Biden laughed off his fall.

Of course, even a good quip can’t stop the realities of growing older. After Mr. McConnell’s freeze, reports raised additional questions about his health since he missed weeks of work for a concussion in March.

For her part, Ms. Feinstein, who has struggled with memory problems and a long absence from the Senate while she recovered from shingles, has appeared at times unable to respond to questions about her condition.

Part of the problem, former aides say, is the interdependent relationship between politicians and their staffs. If a senator retires, his or her entire office — several dozen employees — can be suddenly out of work.

And who wants to tell the boss that they are, perhaps, past their prime? It can be smoother to simply paper over the challenges by having aides craft policy, limit access to reporters and try to avoid unscripted moments.

“The Senate is such a warm, comforting place that you can live inside that bubble,” said Jim Manley, 62, who worked for Senators Ted Kennedy and Harry Reid. “You have staff at beck and call, people opening doors for you all the time.”

While other industries have mandatory retirement ages, including some publicly traded companies and airlines, members of Congress have shown little desire for policies that would amount to voting themselves out of a job. Even voters can’t seem to agree on when enough is enough, remaining divided when asked to back a specific age limit.

The decision to leave a defining and powerful post is difficult, but the alternative — aging in the public eye — might be worse, former senators warned.

“It’s heartbreaking, embarrassing, but it’s up to the individual to come to grips with reality,” said Chuck Hagel, 77, a former Nebraska senator who left office in 2009. “The reality is we are not going backwards; we’re all getting old. At 77, versus 62 when I left the Senate, I have pains now that I didn’t even know I should have.”