Why and how do security institutions evolve? How is it that the European Union security architecture has changed so rapidly over the past ten years, without member states agreeing on a common vision of European integration in this field? This paper engages the current debate on the evolution of the European Union’s Common Security and Defence Policy (CSDP) by investigating the role of knowledge
and ideas in influencing further European integration. Structural and functional explanations – whether realist or liberal – are underdetermining, since they don’t fully account for the process of almost permanent expansion and reform that institutions and procedures underpinning CSDP have undergone over the last ten years. I argue that these theories need to be complemented by an approach emphasizing the role of “knowledge” as a key intervening variable between structure and agency. Accordingly, my research demonstrates that transnational networks of experts have fostered institutional and policy learning by promoting new principled and causal beliefs, leading to new values and strategic prescriptions. From an empirical standpoint, this research focuses on the development of a comprehensive approach to security, and specifically it analyzes the introduction of Security Sector Reform (SSR) principles and practices in the EU security policymaking. Since these new precepts have tremendously impacted on the current shape and activities of CSDP, locating their intellectual cradle and understanding how these norms were diffused its pivotal to gain a clearer idea of the institutions that handles security matters in today’s Europe. While structural conditions after the end of the Cold War underpin the new strategic prescription of “comprehensive approach” and “security-development nexus”, the way communities of experts
responded to these conditions and redefined EU security interests is essential to explain change at the institutional and policy levels
