This article explores the historical evolution of research on the “European Union (EU)–North Atlantic Treaty Organisation (NATO) relationship” since the 1950s and examines the numerous ways in which it has served as an important case study for applying and developing theory-guided and conceptual research on inter-organisational relations (IOR) in International Relations. After a dearth of policy-oriented research during the 1990s and early 2000s, a wide range of scholars have contributed to a “conceptual turn” in the study of EU–NATO relations during the last decade. This development, as this article will argue, not only signifies a stronger interest by scholars to understand the complex relationship between both organisations with the help of more theory-driven research, but also highlights that the EU–NATO relationship has become a “catalytic case study” in terms of inspiring conceptual experimentation and advancing efforts to theorise IOR more generally. The article provides for the first time a systematic stock-taking and analysis of the richness of concepts and theoretical debates related to EU–NATO relations research and offers scholars wider insights into the most promising approaches and analytical tools for understanding and theorising EU–NATO relations.
- EU–NATO relationship, inter-organisational relations, resource dependence theory, overlap, multi-level analysis, population ecology, practice turn, principal–agent theory, isomorphism, theories of inter-organisational relations