Second, this matryoshka doll of supra-nation, nation, and region does have other figures, including the individual and minorities whose rights can be better protected by power centered at the national level. In regions they are vulnerable to oppressive local factions and while in the supra-national or any confederated arrangement they may be sacrificed to preserve the inclusion of the intermediate state or region.

There are counter-examples to my view. Some minorities may fare better in empires (though sometimes at the expense of others, the Sunnis in Iraq under the Ottomans being one example.). Despite its national government, African-Americans in the South both before and after the Civil War had their rights suppressed to form the Union, first, and then as a chip in a political bargain for those in other regions to gain national power.

No doubt, as another commenter observed, there’s just more to it than sizing and structuring the relationships. Madison wrote from the frontiers of the science of politics that now has new frontiers. Still, I am ready to credit him with the appreciation of a fuller range of dangers from which protection was needed.

I would quibble with this example, as there is still a very strong linguistic component to Spanish regionalism (Basque, Catalan, etc.) that regionalism in the US does not have (minor exceptions being the French speaking parts of S. Louisiana, Gullah speakers in the Eastern coastal islands). I’m not sure that someone in Bibalo or Barcelona who feels themselves to be culturally Basque or Catalan would laugh at all, or find their cultural identity to be a petty matter.

That’s interesting, but it begs a further question: What role, large or small, does mass popular culture play in counterbalancing this trend? Regional and state differences, while still not nothing, are surely less pronounced now then they were 200 or 100 or even 50 years ago, as increasingly we read the same books, listened to the same music, watched the same TV shows and movies. Does whatever cultural differentiation that still exists get buried under a mass produced mass consumed pop culture?