ELI5 Please.
I see it Westphalia tossed around as "the origin of the modern nation state" every now and then. I just don't really understand what that means. How is a nation state different than all of the nations and states that existed before the treaty and why did this treaty have an impact beyond the official signatories?
This question has come up a few times over the past year. While there's always more to say, you might like to check out this detailed discussion of the issue led by u/sunagainstgold:
What ideas did "Westphalian sovereignty" replace?
And I commented on the shortcomings of the portrayal of the treaty in International Relations theory here:
Why is the treaty of Westphalia significant?
Other older threads covering much the same ground can be seen here and here.