There’s a juicy family squabble brewing among California’s congressional Democrats. It seems Representative Ro Khanna, freshman standard-bearer for Silicon Valley, was less than thrilled when the state’s senior senator, Dianne Feinstein, announced Monday that she would seek another term in office next year.

Quick as a flash, Khanna started talking smack about DiFi via traditional and social media disses, saying the veteran senator is “out of touch with the grassroots” and urging voters to “jettison her” even as she tries to “cling to office as the voice of the status quo.” A vice-chairman of the Congressional Progressive Caucus, Khanna went so far as to publicly urge Representative Barbara Lee and former Labor Secretary Robert Reich to launch primary challenges to Feinstein from the left. Voters are frustrated, he charged in an op-ed in the Sacramento Bee, “that the turnover rate in Congress is lower than contemporary European monarchies.”

Wow. That’s got to sting coming from a member not just of Feinstein’s own party but also of her own delegation—and a bottom-of-the-food-chain House freshman at that. Whatever happened to respecting one’s party elders—or at the very least not gut-punching them in public?

But here’s the thing: Khanna is kinda right. Not so much about Feinstein’s politics (though the party still has miles to go with its ideological soul-searching) as about her basic desire to “cling to office.”

Feinstein is a highly respected public servant who has been a force in the Senate for more than a quarter century. But—how to put this delicately?—the gentlewoman from California is 84 years old. At the end of another full term, she would be 91. Even accepting the boomeresque blather that 60 is the new 40, one’s late 80s/early 90s are still plenty old. And while Feinstein no doubt still has much to offer, there’s a solid argument to be made that it’s time for her to let the party’s up-and-comers take center stage.

Now, before everyone starts firing off How-dare-you-pick-on-DiFi! tweets, let me clarify: The issue here is not Feinstein per se. Indeed, if she were a Senate outlier, her age would be far less concerning. Every organization needs seasoned veterans. But far from being unusual, Feinstein is simply the marginally oldest member of a body arguably best described as a gerontocracy.

Consider this: More than one-quarter of current Senators are 70 or older. Almost half are 65 or over. Seven are over 80. Since Tom Cotton’s last birthday, no one is under 40. (The minimum age for election to the Senate is 30.)

Many of you must be thinking: Isn’t this kind of talk grotesquely ageist? Who’s  to say that Feinstein—or Chuck Grassley, who’s only a couple of months her junior—aren’t as formidable at 80-plus as they were at 60-plus? Even assuming a bit of slippage, don’t wisdom and expertise make up for declines in physical or mental vigor? Haven’t medical advancements and better health habits rendered age more-or-less a false construct?  

Helpfully, public-health guru Harold Pollack recently tackled many of these questions for Vox.  While stressing that “blanket judgments about older politicians are of course indefensible,” he lamented that Americans’ sensitivity about aging prevents us from having “frank” talks about some of its “elemental realities” and “unavoidable statistical consequences.” From there, he oh-so-delicately pointed to the risks of everything from “disruptive medical tragedies” (like John McCain’s cancer or Thad Cochran’s failing health) to dementia and death which rise ever-more sharply as people cruise through their 60s and 70s on into their 80s.

Looking at just a couple of Pollack’s stats: An American woman Feinstein’s age has less than a 50 percent chance of living another six years (that is, the length of a Senate term). Granted, Feinstein is hardly your average American woman, but physical decline comes for us all—as does mental slowing. As Pollack also pointed out: “Over age 70, almost one-fifth of American adults experience some mild cognitive impairment,” while the annual risks of “real dementia” among otherwise healthy folks “roughly double every five years after age 70.” By 85? Nearly one-third suffer from it in some form.

The most obvious counter to such concerns is that voters get the chance every six years to boot their senator if they suspect he or she is slipping. In theory, yes. In practice, the advantages of incumbency are so overwhelming that it takes something pretty dramatic to dislodge a sitting member (God only knows how many years Strom Thurmond’s staffers actually ran his office). Not to mention, six years can be a mighty long time.

What’s more, it’s not as though voters typically elect first-time senators on the basis of their decades-earned wisdom. Feinstein was initially elected at age 59, Grassley at 47, Orrin Hatch (the body’s third-oldest member) at 42, and so on. The second-oldest Democrat, 77-year-old Patrick Leahy, joined the club at the dewy age of 34. And only one of the seven senators elected last year was over 60: John Kennedy, 65, of Louisiana. But once these folks get that Senate membership, they tend to dig in and stay—and stay and stay and stay.

Again, this is not to single out Feinstein—or Democrats. In fact, after DiFi, the next seven oldest Senators are all Republicans: Grassley, Hatch, Richard Shelby, Jim Inhofe, Pat Roberts, John McCain, and Thad Cochran. The combined age of these seven men is 573 years.

But while Republicans may be in an equally advanced chronological state, Democrats are in a trickier political position. The party desperately needs fresh blood in both chambers of Congress, not to mention the presidential field. (When 76-year-old Bernie Sanders is the voice of a new generation, it’s time to do some soul-searching.) This has become a topic of heated and perpetual (if generally sotto voce) debate among party aides, strategists, and members alike.

“The floors of the Capitol should creak, not the members of Congress,” quipped a veteran Democratic consultant. “Seriously, we are in need of not just younger, fresh leadership but fresh and cohesive ideas,” she said. “How in God’s name are we supposed to convince Millennials we care about student-loan debt when we look like their grandparents?”

In the meantime, the party’s rising stars are being held back, fretted another strategist. “We have so much talent that we are just leaving to die on the vine, which is not only a tragedy for the party but a major deterrent for hungry, smart new members to have a real impact on our platform moving forward.”

Now and then, the tension erupts in public. Earlier this month, California Representative Linda Sanchez dropped jaws when she vented to reporters that it was time for the entire House Democratic leadership team—most definitely including fellow Californian, Minority Leader Nancy Pelosi—to move on: “I think there comes a time to pass that torch. And I think it’s time.”

In Feinstein’s case, the political calculus for making way for new talent comes with way less risk than it would in a swingier state. California is deep blue, meaning that, even without Feinstein’s incumbency edge, Democrats would almost certainly hold the seat—as when long-time Senator Barbara Boxer retired last year (at the tender age of 76) and was succeeded by the state’s then-Attorney General Kamala Harris.

It’s not as though the party lacks young talent in the state, said a former top House Democratic aide, pointing specifically to Lieutenant Governor Gavin Newsom and Harris’s successor as attorney general, Xavier Becerra. “Look at what Kamala Harris has done since she has come in!” he gushed. “But some of the older folks like it and want to stay there.”

And if lawmakers want to stay forever, there’s not a heck of a lot you can do about it, all agree. Term limits are a fun idea to toy with, but since it would be up to Congress to set those limits, no one thinks they are going to happen. Ever. As the former House aide mused, “We were joking the other day: Can’t we have there be an age limit of 80? That would be reasonable.”

And so it falls to individual senators to use their own judgment to decide when they are no longer up to the job. Small wonder that some of their younger colleagues feel increasingly moved to give them the occasional shove.