The treaties of Muenster and Osnabrueck in 1648—the Peace of Westphalia—and the earlier peace of Augsburg in 1555 established the principle in European international law that internal affairs were nobody else’s business.
No, it didn’t.
In addition to stipulating a number of territorial adjustments, the Peace of Westphalia:
- Reformed the Imperial Constitution to create non-violent processes for adjudicating religious disputes;
- Reduced the authority over religious matters accorded to German princes in the 1555 Peace of Augsburg; and
- Generally revitalized the Empire as a supranational political entity.
Indeed, far from affirming the notion that the “internal affairs” of European states were “nobody else’s business,” Westphalia designated France and Sweden as guarantors of its provision, including, as Benjamin Straumann notes (PDF), “the constitutional provisions for the Empire contained therein.”
Brad’s post — a long rumination on World War II — is otherwise a tour de force.
See: Andreas Osiander, “Sovereignty, International Relations, and the Westphalian Myth,” International Organization 55,2 (2001) (Gated PDF); Benno Teschke, The Myth of 1648: Class, Geopolitics, and the Making of Modern International Relations (London, Verso, 2009); and Daniel Nexon, The Struggle for Power in Early Modern Europe: Religious Conflict, Dynastic Empires, and International Change, Chapter 8 (Princeton University Press, 2003).