A near impossible literacy test Louisiana used to suppress the black vote

I know, from a human rights point of view, this is very problematic. But imagine, if only people who can really understand written text, who can calculate, who understand how legal system works, who have basics of logic could vote.

Of course, those tests shouldn't be that ambiguous, but if they were phrased a bit more clear, these would be very simple. At the same time, English has changed in the last 50 years. That phrasing might have been common back then.

This is the key problem of democracy, the educated part of the society is always minority.

I don't think education do much. People still stupidly vote for one of either republicans or Democrats based on trivial psychological reasons.

If education played some role you would probably might have seen an alternative party/form of government emerging over time as people became more educated.