Why do political party families, big and small, without exception, engage increasingly in transnational collaboration, in arenas like the European Parliament and beyond? What do they hope to gain from it, and what might they fear losing? Beyond the Nation State looks below the usual rhetoric of party families to trace some deep-lying historical processes and patterns. Experiences can vary within and between families, but the overall patterns are clear. Based on numerous interviews and studies of national parties, the book shows these parties to be reluctant participants in a process of party integration which they may well have to take further, despite their doubts.