Any system based on medical or intellectual tests is doomed to fail. There’s a reason we had to end literacy tests. Any test has to have people that design, administer, and grade the test. Age limits are a crude and blunt instrument, but there is a reason we use them for other matters of politics in the early stages of life. We have a voting age, not a voting competency test. And we have minimum ages for House, Senate, and Presidency eligibility. Yes, you could try to write qualifying exams for these positions, but the history of literary tests shows how that would go. Age is a crude instrument, but it is objective. You were born on certain day, and assuming accurate public records, that is a fact that isn’t open to interpretation. It is clear and unambiguous.

An age limit for high offices makes perfect sense. If we can have minimum ages, we can have maximum ages. And any argument for why maximum ages won’t work would also apply to minimum ages, yet our constitution is based on minimum ages, not fuzzy ability tests.