Presidential math

This came up in one of my classes for math teachers... James Garfield holds a novel distinction of being the only US President who has authored a proof to the Pythagorean Theorem (you know, square of the hypotenuse is equal to the sum of the squares of the legs of a right triangle). What's even cooler is that the proof isn't that tough to understand, it's high-school level geometry. Why isn't this a requirement for the office?

[reading Garfield's bio, I just have to quote this: Garfield was the first ambidextrous president. He could simultaneously write in Latin with one hand, and Ancient Greek with the other. What, were there others?]