How old is too old to be president?

President Biden is 79 years old and would be 83 at the time of his inaugural if he wins a second term. If he served the full term, he would leave office at the age of 87. Former President Trump is 75, and should he run again and win, he would be 79 when sworn in and 83 by the end of his term. At these ages, most families are trying to figure out how to take their dad’s or mom’s car keys away from them. But, under the Constitution, we would be obliged to hand over the keys to the Oval Office, the world’s most powerful and demanding office.

Shouldn’t there be an age limit on who can run for president?

The Constitution already specifies a minimum age to become president: 35. The Framers obviously thought that setting a minimum age was necessary to ensure that the nation’s chief executive would be relatively mature and have some political or military experience to call on. While they knew that there could be 25-year-olds equally ready to assume the office’s powers and duties, they were unwilling to open the door to such brilliant exceptions precisely because exceptions are not the norm and a constitution cannot take such chances if it wants to last over time.

Nowadays, we certainly live longer and lead generally healthier lives, whether from better habits or the prescriptions that fill up our medicine cabinets. But it’s still inescapable that, as we get older, virtually all of us slow mentally and physically. Here, too, there are exceptions. Everyone has heard about the grandfather still playing pick-up basketball on a city playground or a grandmother still pounding out her umpteenth novel. Nonetheless, a governing document should not presume luck in the genetic lottery.

Nor does the test of America’s prolonged presidential campaigns guarantee voters will have an accurate handle on a candidate’s mental and physical health. Campaigns are good at hiding whatever problems exist, and voters rarely see anything but the best in their preferred candidate. And even if the public had access to thorough and honest medical records of the candidates, those records cannot guarantee a president’s future mental and physical health. Moreover, as we now know, the fact that a president is not well rarely becomes public at the time.

Arguably, the existing failsafe is the 25th Amendment, which allows an ailing president to step down in favor of his or her vice president or, if unwilling to do so, a mechanism by which a vice president and a majority of the Cabinet give notice to the Congress that the vice president will be assuming the office’s powers and duties.

But this process has its own flaws. Presidents rarely believe they are not up to the job, no matter how sick, and getting a Cabinet made up of presidential appointees to engage in a “soft coup,” especially against an unwilling president rallying his own partisans against the effort, is a very steep and convoluted hill to climb. 

It seems better to head off reliance on this messy and uncertain process by amending the Constitution to set an age limit on who can become president.

Drawing that exact line (at say, 70) will admittedly be judged as being arbitrary. All lines of this kind are. But arbitrary does not mean unreasonable if based on a judgment of what generally makes sense. Ronald Reagan was, until Trump, the oldest person elected president at 69. And by the end of his second term, he was no longer, as some have noted, functioning like “the Gipper.” 

The presidency is unique among our system of separated powers in that, unlike Congress and the Supreme Court, it is never is out of session. The reason the founding generation determined that the president alone should have a house is that the chief executive’s job is 24/7. Perhaps when life expectancy was shorter, the Constitution’s framers thought there was no need to put a cap on how old a person might be to be president. That is no longer the case and we’re rolling the dice by ignoring that change and the obvious downsides of having no limit on how old a president can be.

Gary Schmitt is a senior fellow in constitutional studies at the American Enterprise Institute.