The centralized nation-state was the outcome of political evolution. Whatever the merits of the nation-state, it became apparent in the twentieth century that it did not prevent the mounting horrors of war, and that alone it could not ensure economic prosperity. As a result, efforts were made to develop new political devices. The preferred solution among those of liberal outlook was the ‘international institution’. The aftermath of the First World War saw an attempt at institutional order through the League of Nations; the close of the Second World War brought the United Nations and a range of other more specialized bodies, some almost worldwide, others of lesser scope.

In Europe, the cradle of the nation-state, the most advanced attempts to develop a new institutional order are to be found. The idea of the nation-state as an ultimate, compelling reality was brought into question in Western Europe by the Second World War more widely and profoundly than had been the case after the First World War. The governments that had fused extreme nationalism and dictatorship, Nazi Germany and fascist Italy, were buried in the war of aggressive brutality they had unleashed. International relations were restructured by alignments of states dominated by the new military superpowers. The battered nations of Europe were corralled into one or other of the two great blocs as world politics became dominated by the Cold War.