Quick show of hands, who knows what Westphalian sovereignty is? For those of you who don’t want to read through the entire Wikipedia article, it’s the principle that any nation state has the right to govern itself and its internal affairs without interference from other nation states, and that each state is equal under international law. (Though it all frequently plays out differently in practice.) Westphalian sovereignty originated with the Peace of Westphalia, a series of treaties that ended the Thirty Year’s War and the Eighty Year’s War in Europe, who had had so many wars by that point they just gave up on original names. Prior to the Peace of Westphalia, constant meddling in the affairs of other countries was completely normal. It should be noted, of course, that the interrelation of royalty throughout Europe was a big cause of this.
Real quick, I want you to look at a map of Middle Earth. Feel free to look up a higher resolution one if you want, but there aren’t any precisely defined borders on the map- there isn’t any sharply defined line between Gondor and Mordor, other than the obvious geographic features. This isn’t because J.R.R. Tolkien just decided to draw a geographic map of Middle Earth and call it a day- the omission of borders was deliberate. This is, admittedly, speculation on my part- I don’t know for sure that Tolkien was deliberately modeling the nations of Middle Earth after pre-Westphalian states, but it seems extremely likely. The man was an exceptionally knowledgeable student of European history- for him to have included the strictly defined Westphalian state seems extraordinarily unlikely.
And indeed, in a reading of The Lord of the Rings and the Hobbit, the only borders really mentioned are geographic ones, and nations don’t even pay lip service to noninterference in each others business- which, of course, tends to be rather secondary, since they aren’t novels about nation states, but of good versus evil.