Majority is one issue, "local majority" is another. A country can have 10 distinct regions, and a centrally controlled group can visit them in turn thus "appearing" 10 times stronger.
That is, when this group visits one region, its size needs to be comparable in size with the the particular region only. When it visits a region it can put its "people" in charge.
In theory the "good people" can find strategies to counter this, but I believe it is very hard to do so in practice. People are just not ready for the decentralization it requires.
True, that is the biggest problem
