Why was a security arm of the European Union created in post-Cold War Europe? Why did it succeed when earlier attempts failed to create a viable institution? Standing before a crowded Bundestag on November 28, 1989, barely a year before German reunification, the then Chancellor Helmut Kohl made a rather bold promise to Germans and Europeans. “We have always regarded the process leading to the recovery of German unity to be a European concern,” he said. “It must, therefore, also be seen in the context of European integration.” Over the next decade, German leaders played a pivotal role in the construction of a European security arm tied to the European Union. Past efforts such as the European Defense Community, the Fouchet Plan, and European Political Cooperation failed to create a European – as opposed to a transatlantic – security institution. But this was different. German leaders strongly favored and helped create an EU security arm as part of the Treaty on European Union (1992), and pressed for deeper EU security cooperation at Amsterdam (1997), Helsinki (1999), Nice (2001) and beyond. Germany's behavior and the variation in European security institutions pose an interesting puzzle.

This chapter explains why European states have constructed an EU security institution in the post-Cold War era – what I call a “binding” strategy – and why they failed to do so during the Cold War. In order to do this, this chapter lays out the conditions under which states might choose a binding strategy.