Though Senator Ed Markey has already been in Congress for 49 years, he wants voters to reelect him to another six-year term. He will be 80 on Election Day in 2026 — older than any other senator seeking reelection and older than any senator in Massachusetts history. Markey has a tendency to repeat himself; for years his answer to questions about stepping aside has been word-for-word the same. “It’s not your age, it’s the age of your ideas,” he invariably says. “And I’ve always been the youngest guy in the room.”

But that line is glib nonsense. Some of the “youngest” ideas in circulation, like the vogue for socialism among Generation Z, are thoroughly foolish, while some of the very oldest ideas in American history — “We hold these truths to be self-evident, that all men are created equal” — have never been improved upon. Just as age does not always lead to wisdom, the newness of one’s “ideas” is no guarantee of their good sense or practicality.

As for being the “youngest guy in the room,” if the room is full of Massachusetts politicians it is likely to resemble a geriatric ward.

Political power in the Commonwealth is concentrated in the hands of the elderly. Markey’s Senate colleague Elizabeth Warren is 76, as is Representative Richard Neal, the dean of the state’s delegation in the House of Representatives. Nearly as old are two other House members, Bill Keating, 73, and Stephen Lynch, 70. On Beacon Hill, the ages skew even higher. Representative Paul Donato of Medford, Senate Majority Leader Cynthia Creem, and Senator Pat Jehlen of Somerville are all in their 80s. House Speaker Ron Mariano is 78, Senate President Karen Spilka is 72, and Secretary of State William Galvin — first elected more than three decades ago — turns 75 next month. In a state whose median age is 40, and which has long been a mecca for college students from around the world, the gerontocracy could hardly be more firmly entrenched.

That imbalance would be troubling enough on its own. But what makes Massachusetts politics especially perverse is the way we enforce strict limits on age and tenure in some spheres of public life while turning a blind eye to the advancing years of our political leaders. The inconsistency is glaring.

Under the Massachusetts Constitution, for example, the state’s judges must retire by age 70, regardless of their mental sharpness, legal deftness, or desire to keep working. The logic behind the rule is straightforward: At a certain point, the risks of mental decline outweigh the benefits of experience, and it is better for the institution to guarantee regular turnover than to cling to the talents of a few elders.

Even more straightforward is the reason why Massachusetts law requires firefighters, police, and correction officers to retire by 65: because no matter how much experience a uniformed public safety employee brings to the job, there comes a time when diminished strength and slower reflexes make continued service a potential danger to the public. Well, it is also potentially dangerous to the public when legislators cling to office long past the age at which firefighters and judges are permitted to do so.

Massachusetts voters appear to recognize the problem. In a University of Massachusetts/WCVB poll last October, 72 percent of respondents said they would support an age limit for US senators; on average, respondents favored a cutoff of 66. Yet at the ballot box, incumbents keep getting reelected, usually unopposed, even into their 80s.

The problem isn’t limited to Massachusetts, of course. In Washington, it grows ever more painfully obvious that Congress is filled with men and women who cannot bring themselves to admit that their time has passed.

One recent jarring example was former representative Kay Granger, a Texas Republican, who vanished from Capitol Hill and missed scores of votes — because, it turned out, she was residing in a senior care facility in Fort Worth after developing dementia. Representative Eleanor Holmes Norton — the 88-year-old who has represented the District of Columbia in Congress for 34 years — continues to insist that she will run for a 19th term, though everyone can see that cognitive decline has left her “vastly diminished and struggling to fulfill her congressional duties,” as The New York Times reported in June. And recent history has brought numerous other examples of sick, superannuated lawmakers, including Senators Dianne Feinstein and Ted Kennedy, who refused to retire and died in office.

Unlike Markey and too many other Massachusetts politicians, one towering figure of recent memory had no qualms about retiring at a sensible age. Tip O'Neill, the Cambridge congressman who rose to become speaker of the House, voluntarily stepped down in 1986 at 74. Asked why, he answered bluntly: “How long you gonna stay around here? I figure it’s time to get out.” It was the decision of a leader who understood that public office should be a season of service, not a life sentence.

If voters today insisted on seeking out more Tip O'Neills — politicians who knew when to quit and who were not so addicted to office that they clung to it until dementia or death — the gerontocracy would evaporate. The only sure cure for our plague of endless incumbency is for the electorate to stop indulging it. No one forces Massachusetts voters to be represented by politicians past their sell-by date. If you really want “the youngest guy in the room,” try electing someone who isn’t pushing 80.