They go hand in hand...small countries (geographically) like Singapore or Estonia can arrange themselves in a single layer, where the central government control

They go hand in hand...small countries (geographically) like Singapore or Estonia can arrange themselves in a single layer, where the central government controls everything down to the police and parking meters. Large countries like Canada, Mexico, or the United States tend to arrange themselves into states, provinces, counties, and cities with some degree of autonomy. I suppose there could be a large country with a single layer or a small one with multiple layers.