The idea of national sovereignty started mainly at Westphalia. This was different from the way people and groups had been divided before. But the idea of national sovereignty and non interference with another nations internal polices has become so prevalent that we forget that it is by no means an obvious division.
I think that at present we are facing a new kind of division among men--Islam against Western Civilization.
Clearly Islamic nations do not accept the ideas of Westphalia except in so far as they can make progress in subjecting the rest of the world to their religion