The definition of "Democracy" causes many problems.
The original article is here. Essentially, they were income level (wealth), education, industrialization, and urbanization (from memory). Much more study had been done particularly in the 1990s to explain why democracy beat out communism. In any case, most of this was well known.
Isolated localities often use some form of "democracy" in that the heads of the local households get together to decide matters that concern all. But this is not the liberal democracy as we know it with universal human rights.
Rule of Law is problematic, because that translates into procedural legitimacy, which simply means that you are following the social norms and rules of the society . Stoning a women for being raped may represent the appropriate action. Interfering with that stoning may be seen as failing to uphold the rule of law. To often these vague terms are tossed around like they have a common meaning. They do not.
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