The Presidency Is Not a Math Test

Updated at 9:47 a.m. ET on February 13, 2024.

Sign up for The Decision, a newsletter featuring our 2024 election coverage.

At the height of the Iran-Contra affair in 1986, Saturday Night Live featured a now-classic skit in which Ronald Reagan (played by Phil Hartman) doddered around the Oval Office whenever a journalist or tour group showed up, then snapped into evil-genius mode when they left the room. “Casey!” he barks at CIA Director William Casey. “The TOW missiles and grenade launchers will leave for South Africa at 0800 hours!” He performs lightning-quick mental arithmetic to improvise funding for a covert op. Those who lived through the second Reagan administration may remember the alarm at the president’s creeping senility. That someone with a declining mind and a preoccupation with the apocalypse had to make decisions about thermonuclear exchanges with the Soviet Union was so unsettling that to keep sane, one had to crack jokes about it.

President Joe Biden was only in his forties when that SNL skit aired. Some 38 years later, Special Counsel Robert Hur’s report exonerating Biden in a classified-documents case took palpable digs at the octogenarian’s acuity. Biden reacted angrily, particularly at the assertion that he could not remember, “even within several years,” when his son Beau had died of brain cancer. Many people already think Biden is senile, and now they think they have a legal document certifying their judgment. The document does not quite say what many believe it does. It doesn’t say that Biden is unfit to stand trial, just that he’s forgetful enough to evade conviction on the basis of a particular utterance. But that’s already a mortifying judgment. Reagan made many weird and alarming comments suggestive of mental decline, but none that were officially interpreted as dotty-old-man-talk by the Department of Justice.

Having a president who whiffs factual questions about the most important events in his life is not ideal, except maybe for the purposes of late-night comedy. But old age remains underrated. Four years ago, I wrote about the upsides to having a president teetering on the brink of senility: Yes, certain mental faculties decline with age, but others get slightly better, and in the latter category are faculties relevant to being president. The type of senility that should fill voters with dread is not losing track of a document or a date. It’s a catastrophic crash in the ability to make good decisions. One can doubt the wisdom of Biden or Donald Trump—but those doubts probably applied four years or even 40 years ago. Neither of the old men running on a major ticket shows any sign of senescence of this sort. Whatever defects of judgment they have are long-standing.

One’s ability to do mental arithmetic starts to go down in early adulthood, and it never recovers. But one’s judgment, the ability to make certain types of difficult, marginal decisions, persists through most of human aging, and might even improve with accumulated experience. The presidency is an endless series of judgment calls, not a four-year math test. In fact, large parts of the executive branch exist, in effect, to do the math problems on the president’s behalf, then present to him all those tough judgment calls with the calculations already factored in. The National Security Council, for example, does little else but funnel facts and analysis to the president and coordinate the execution of the decision he makes. The president is, as George W. Bush put it, the Decider. The whole joke of the SNL sketch is that Reagan the Decider is doing the work of the Calculators, too, and virtuosically. That is about as ridiculous as a president personally cooking the soufflés at a state dinner.

Helen Lewis: Biden’s age is now unavoidable

Insofar as the presidency is a Decision job, we should expect old presidents to compete well with young ones. And scholars’ judgments bear that prediction out. On most lists of great presidents, one sees little correlation between high marks from historians and the president’s age while in office. (Reagan was, before Biden, the oldest sitting president, at nearly 78. Trump left office at 74, and the next-oldest president was Dwight Eisenhower, a mere spring chicken of 70 when he retired.) When I read Special Counsel Hur’s commentary on the president’s fumbling for a date, I wince. But I am not alarmed, in the way I would be if I heard that Biden showed an unusual lapse in judgment by making decisions that were not just bad (he has made his share of those) but erratic and out of character. He could inexplicably embrace world leaders he recently reviled, or offend allies for equally bizarre reasons. I see little evidence that Biden’s judgment is getting worse.

The big age-related risk is not the slow slippage of mental faculties but terminal deterioration—the fast failure of mental faculties across the board. And because the risk of catastrophic cognitive failure rises with every year of old age, and often precedes death by a year or two, I would consider it foolish to elect anyone as president who can be expected, actuarially, to die within five or six years of taking office. Actuarial tables suggest that white men in their mid-to-late-80s are about five or six years from the grave. (Biden will be 82 on Inauguration Day.) This calculation does not consider the effects of other age-related decline, such as having less energy. I like a nap as much as the next person, but one proven habit of effective presidents is that they are awake for most of the day.

A few weeks ago, Trump boasted of having aced a cognitive test meant to measure senility. This is like boasting of having aced a panel of tests for venereal disease: Ideally one’s physician would not be ordering such tests, and one would not brag about the results either way. But the accusations of senility seem mostly to stand in for other suspicions of incompetence. How convenient would it be, for one’s political enemies to be medically proven unfit for their jobs! (A finding of medical unfitness is in this respect nearly as satisfying as the prospect of a finding of legal unfitness.)

These certifications offer false hope. Completing a full presidential term, even badly, is a rather demanding cognitive test, all by itself, and both candidates have recently passed it. Before any psychometric examination is needed, candidates should be excluded based on the presence of ordinary, nonmedical characteristics: stupidity, venality, amorality, indecency, and plain old fondness for bad people and bad ideas. There is no medical test yet developed to weed out these deficiencies. There is a nonmedical one that is highly imperfect but the best we have developed so far. It’s called an election.

Due to an editing error, this article originally misstated Joe Biden's age in 1986.