Joe Biden’s campaign has been dogged by questions about whether, at age 77, he is still healthy and mentally acute enough to serve out a full two-term presidency. But now, Politico’s Ryan Lizza reports, advisers close to the former vice president are saying that he likely wouldn’t even try.

According to four people who regularly talk to Biden, all of whom asked for anonymity to discuss internal campaign matters, it is virtually inconceivable that he will run for reelection in 2024, when he would be the first octogenarian president. “If Biden is elected,” a prominent adviser to the campaign said, “he’s going to be 82 years old in four years and he won’t be running for reelection.”

Some in Biden’s circle are urging him to make a public one-term pledge, which would let him campaign as a “transition figure” capable of drubbing Trump in the general, before quickly passing the torch to a younger bunch of Democrats.

This is far from a done deal: The candidate himself is wary of making any explicit promises, for fear that it would immediately make him a lame duck. And another adviser told Lizza that Biden is at least open to sticking around for eight years: “He’s going into this thinking, ‘I want to find a running mate I can turn things over to after four years but if that’s not possible or doesn’t happen then I’ll run for reelection.’ ” In the meantime, Biden is keeping his on-the-record answers on the second term question vague—“I’m not going to make that judgment at this moment,” he told the Associated Press in October—and on Wednesday his staff tweeted what amounts to a nondenial.

Lots of chatter out there on this so just want to be crystal clear: this is not a conversation our campaign is having and not something VP Biden is thinking about. https://t.co/mXNEnX6GrU — Kate Bedingfield (@KBeds) December 11, 2019

Notice the statement does not say that Biden definitely intends to serve eight years in the White House. And if he doesn’t, then he really shouldn’t be campaigning for it in the first place.

For starters, if Biden thinks there’s a chance he simply won’t be able to handle the job in five or six years, he should realize there’s a chance he won’t be able to do it in two or three either. Being president is hard; it tends to age politicians rapidly, and Biden shouldn’t gamble on his ability to fill the role.

But beyond all that, serving as a one-term president will vastly diminish his powers in office and possibly set back Democratic policy priorities. It’s not a fix for anything.

One of the most important parts about being a first-term president is running for reelection. It gives you leverage over your party on Capitol Hill, since lawmakers want to help you nab that second term or at least don’t want to piss off primary voters by denying you legislative wins and undermining your chances. Plus, you can do more in eight years than four. You get more time to appoint judges. You can implement legislation that takes a while to get up and running. (The Affordable Care Act’s exchanges didn’t even start selling insurance until Obama’s second go-round.) And even if the opposition takes over Congress, you can still use the Justice Department and regulatory agencies to push change. (Donald Trump, for instance, is cutting food stamps at the moment by administrative fiat.)

Best yet, barring a geopolitical disaster or a recession, sitting presidents also tend to win reelection. Of the 11 post–World War II elections involving one, the incumbent has won eight times. (The record falls to eight out of 13 if you include the years Harry Truman and Lyndon Johnson chose not to seek what effectively would have been third terms.) The power and prestige of the office combined with status quo bias among voters and many people’s basic unwillingness to admit they might have made a mistake the last time they cast a ballot all seem to give incumbents a large built-in edge. Just by winning a four-year term in office, you make it much more likely that your party will get to govern for eight.

If Biden signals that he really doesn’t want a second term, he will throw all of those advantages away. As the man seems to realize, he would enter office a lame duck, making it harder to pressure recalcitrant senators to go along with his legislative proposals. He’d only have four years to enact his agenda before his successor took over. And Democrats would lose the benefit of running a sitting president in 2024. Maybe his hand-picked successor would inherit all the benefits of incumbency. Maybe he or she would turn into another Al Gore or Richard Nixon, who lost bids for the White House despite serving presidents with high approval ratings. Or maybe one of the two dozen other Democrats who’d like to be president would win the primary.

A “transitional” Biden presidency risks becoming one in which Democrats pass few significant pieces of legislation before Republicans retake control of Washington and promptly begin reversing their achievements. It would make significant progress on climate change—which is theoretically one of Biden’s top issues—especially unlikely, since it will take years to ramp up any program designed to reduce U.S. carbon emissions, and recalcitrant moderates like Joe Manchin will have even less incentive than under a normal presidency to support any green legislation. In other words, a “transitional” presidency is more likely to be a failed presidency.

Some will no doubt point out here that if Democrats don’t beat Trump now, the party won’t be able to govern at all. But a weak, four-year presidency that starts in 2020 might actually be worse for progressive priorities in the long term than a stronger presidency that begins in 2024. Democrats would even have a chance to pick up Senate seats running against Trump in the 2022 midterms, when the map will be much friendlier than it is in 2020.

So then why is this one-term talk even happening? If you are a conservative-leaning never-Trump voter, picking Biden for a one-and-done run at the White House might make perfect sense. He’s likely to get rid of the great orange menace and act as a caretaker before a more respectable Republican takes over again in as little as four years.

For a Democrat, though, it’s only rational if you believe two things simultaneously. The first is that Donald Trump’s presidency poses a singular, existential threat to the country, and that returning politics to “normal” by beating him is so important that it outstrips any other long-term priority. The second is that Biden is so uniquely electable against Trump that it’s worth sacrificing the advantages of a two-term presidency in order to get the job done. Not coincidentally, these are two of the Biden campaign’s two main talking points these days.

Is Donald Trump an awful president? Yes. But he’s also very much a symptom of the modern Republican Party. His views on immigrants and Muslims are popular with the party’s base—that’s why he got elected in the first place—and the next Republican president may very well share them. And insofar as he’s attacked our democratic institutions, he’s been abetted by Republicans in Congress who have decided to defend him from being held accountable, even if it means latching onto his ludicrous conspiracy theories. His judges are, for the most part, the same movement conservatives that Mike Pence would pick. We can get rid of Trump, but every sign suggests Trumpism will live on.

But there’s a more basic point here: Biden isn’t the only Democrat capable of beating Trump. He polls best against the president, sure. But in national surveys, Bernie Sanders, Elizabeth Warren, and even Pete Buttigieg are also winning in head-to-head matchups at the moment. There is simply no reason Democrats need to sacrifice their chance at a normal presidency for the sake of electability. Joe Biden shouldn’t ask them to do so. If he knows he’s too old to serve two terms, he should know that he’s too old to serve one.