Not that this will do any good, but ... people persist in mischaracterizing the Peace of Westphalia.
I'm skimming through a piece by Geoffrey Wheatcroft, called "Once Upon a Time in Westphalia" (ungated) in the current issue of The National Interest -- lots of nice quotations, Rev. Sydney Smith, Cobden and Bright, yes, yes, etc. Then my eye falls on a sentence which says that the Peace of Westphalia "established the principle of national sovereignty" (uh-oh) and that it also established the principle of cuius regio eius religio (whose the region, his the religion). Both statements are wrong, though the second one is perhaps a bit more excusable inasmuch as it confuses the Peace of Westphalia with the Peace of Augsburg. The first statement, about Westphalia and "national sovereignty," doesn't confuse anything with anything else; it's just wrong. There are some people who argue that Westphalia helped lay the foundations for a sovereign state system, though even this claim is debatable, but to say it "established the principle of national sovereignty," in an article full of other historical references, is not good.
May I suggest that Mr. Wheatcroft read the text of the treaties of Munster and Osnabruck (or at least the former). They're online.