I'd like also to point out the stupidity of the consideration that all people are or should be equal before the law.
The stupid, having IQ so low they cannot graduate from high school, notoriously make stupid choices, which explains the term "stupid" in reference to them. They cannot compete for the better jobs and mates, and so they gravitate to crime and welfare abuse to get by.
That means the rest of society must support them or pay to defend against their criminal behavior. Bottom line: unsupervised, the stupid become criminals.
So it constitutes a crime against humanity to procreate a stupid child. Society could prevent that crime by outlawing knowing infliction of a debilitating disease (stupidity) on an innocent baby. That would justify sterilization of the stupid.
And since the stupid make stupid choices, of course they should not vote. Furthermore, the smart, making smarter decisions than the mediocre, should have more votes than the average. So the law should never allow universal suffrage, and the suffage it does allow should let the smart and educated and responsible and productive have more say than the non-so-smart, less educated, less responsible and productive.
One can easily make the case that the stupid and irresponsible, having the right to vote, have put criminals into government, and will do that to a greater extent as they increase as a percentage of the population.
The stupid and irresponsible do increase as a percentage of the population because they procreate at nearly double the rate needed to sustain the gene group, whereas the smart procreate at less than the rate needed to sustain the gene group.