If you don't want "illiterates and nincompoops" deciding the course of civilization, the solution is better education and a stronger sense of civic duty (both of which are currently anithetical to American culture,) not the creation of a caste system whereby only some arbitrarily defined intellectual and cultural elites get to vote.

History is filled with the graves of governments ruled by such policies - since education and literacy were the sole privilege of nobility for much of civilized human history. It didn't work out well for the ruling class or the peasants.