[klank]

Had to look up "Schelling point", so apologies if I'm not fully grasping what you mean by it.

However, "organized around ethnic, cultural, and/or linguistic grounds" seems like another way of saying "social construct".

If you were to compare and contrast what you suggest with a social construct how would they be different?

[defen]

Too often I see people argue "X is a social construct" as a way of arguing that X "doesn't exist", or that people who believe in it have a kind of false consciousness.

I'm trying to show why people believe in it. Yes, it's a social construct; but that doesn't mean it's worthless - "money" is also a social construct: it only has value because other people think it has value.

The nation appears to be the largest stable unit of organization humans are capable of, at present at least. The history of the world has shown that Empires don't last too long these days.