I might have missed it but I am pretty sure no one has mentioned the Electoral College yet. Not exactly IQ based but still the same idea, can't let the peons have any power, only the ubermensch is qualified. All humans are equal in some ways, such as basic needs for starters, it is that common equality that makes us all have an equal stake in our government and therefor we should all have equal say. Besides if you are really stupid you probably can't find the voting booth.