Humanity would probably have to eliminate psycho/sociopathic behavior. Something like 1% of humanity (much higher rate in billionaire and CEO populations, like 25%+).
Like you said, designing a system that prevents them from taking control without pretty draconian measures that are likely to catch many false positives (and still be evaded by skilled psycho/sociopaths) seems pretty difficult.
Maybe AI will be able to filter them out of the population, but that’s full of moral and ethical pitfalls too.