The problem with that is that there's x% of the voters that won't count, and parties would argue about the correct value of x interminably, especially if the va

The problem with that is that there's x% of the voters that won't count, and parties would argue about the correct value of x interminably, especially if the value of x determines who is the winner of the election. That can also end up like the "literacy tests" that were used to disenfranchise certain voters based on their skin color.