Not a bad idea that. I believe Heinlein put forth that notion in one of his books. (He'd have the voting machine give you a quadratic equation to solve, which would weed out a whole bunch of people)
It would be Constitutional too. The constitution's protections of the right to vote only extend to denials based on race, color,previous condition of servitude, failure to pay a poll tax, or age for those 18 or older.
That said, I'd prefer the requirement be put into a Constitutional Amendment. Safer that way, from several angles.
Dammit Gato, don’t get us started on Heinlein, in whose hands this entire planet should have been placed ages ago.
So many vote their EMOTIONS instead of their LOGIC.
Just like Saturday horse race bettors.