Treaties: From Westphalia to the United Nations

Alongside balance-of-power politics and shifting alliance systems, the third recurring tool for restraining nationalism has been the peace treaty itself – the formal document nations sign once a war has already burned itself out, meant to fix the political order well enough that the next war doesn’t follow immediately behind it. The record of these treaties across three centuries is a genuinely mixed one, part real success and part cautionary tale.

Westphalia and Vienna: Treaties That Held

One of the earliest and most consequential is the Peace of Westphalia, signed in 1648 to end the Thirty Years’ War. What made it significant wasn’t just the war it stopped, but the fact that nearly every major European power took part in negotiating it, establishing for the first time something resembling a formal, continent-wide set of international rules rather than a patchwork of bilateral arrangements. The 1815 Congress of Vienna, called after Napoleon’s defeat, did similar work on a larger scale, laying institutional groundwork for the balance-of-power system that would structure European diplomacy for the following century and reorganizing the territorial rights of states such as Poland, Austria, and Russia that had been upended by two decades of war.

Frankfurt to Versailles: Treaties That Planted the Next War

Not every settlement aged as well. The 1871 treaty that followed Germany’s unification and its war with France stripped France of Alsace-Lorraine, and that single territorial decision hardened into decades of Franco-German resentment that fed directly into the tensions culminating in the First World War. The peace process that followed that war carried its own warning built into it: the 1919 Paris Peace Conference, and the League of Nations it created the following year, were explicitly designed to dampen exactly the kind of destructive national rivalry that had just devastated Europe – and despite that intention, the League’s failure to actually enforce peace is now understood as one of the conditions that let the Second World War break out in September 1939 barely two decades later.

The Unfinished Question

The United Nations, founded once that second catastrophe had run its course, was built with the same basic goal the League had failed to achieve: curbing destructive nationalism and protecting the rights of minorities caught inside states that didn’t always represent them. Whether it has actually succeeded where its predecessor failed is a question serious observers still weigh rather than one with a settled answer – which is, in its own way, the pattern running through the whole history of treaty-making as a check on nationalism. Every generation’s peace settlement is judged a success only in retrospect, once it becomes clear whether it actually held or simply set the terms for the next round of conflict.