Explaining security and defence integration: the case of Europe

What is driving the European Union (EU) to integrate in matters of security and defence? Why has the EU since the 1990s, and in fits and starts, built up defence institutions, published strategic documents, or launched security missions around the world? This dissertation suggests an answer to these questions that hinges on there being a security community in Europe within which states do not feel threatened by one another. Understanding the level of trust EU states have in one other as well as its bearing on the way they engage in negotiations about the management of their security is of fundamental importance when attempting to make sense of the emergence of the EU as a security actor. States within Europeâs security community and during the period covered by this thesis (1990-2016) suffered numerous external security shocks. These ranged from shifts in the geopolitical landscape surrounding them, to terrorist attacks to immigration crises. Shocks of this nature exposed the externalities of non-cooperation to policymaking elites in EU Member States, ultimately pushing them to seek the elevation of crisis management to the EU level. The outcome of the intergovernmental negotiations that followed each external shock depended on the degree of strategic interest overlap across EU states. This thesis makes evident that as EU integration in other fields progressed a form of spillover occurred where strategic interests converged and a common security and defence policy became an ever more attractive proposition. The narrative suggested in the following pages also explains why EU Member States have sometimes been forced to attend to their security and defence affairs alone. This occurred when they were faced with a crisis with little impact on the strategic interests of other members of the security community. The complicated interactions between the EU and the North Atlantic Treaty Organization (NATO), in turn, can also be seen through this theoretical lens and with the Alliance shielding Europeans from shocks or from the management of their consequences, therefore disincentivizing further EU integration in the field of security. By taking the perspective of EU member states and looking at specific shocks and the reactions they produced the following pages provide an innovative take on a much-studied but poorly-understood subject. They also seek to bring together two relevant but almost entirely disconnected sets of literatures: broader international relations theory and empirical works on European security.