“Taming the Storm” of Hybridity: The EU-NATO Relationship on Countering Hybrid Threats - From Functional Overlap to Functional Cooperation

This article investigates why relations between the European Union (EU) and NATO in the area of countering hybrid threats have been characterised more by cooperation rather than by rivalry. By examining the onset and development of the EU-NATO functional overlap in this policy area, the article explains the factors driving the two organisations’ functional cooperation. Using an eclectic approach that integrates institutional overlap theory and considers both systemic factors (international shocks) and unit-level factors (resource dependence), this research reveals how cooperation has evolved. A key focus is the role of informal relations and the pivotal function of the European Centre of Excellence for Countering Hybrid Threats (Hybrid CoE) in facilitating this cooperation. This article makes an original contribution by addressing an empirical gap in the literature through a theory-driven analysis of EU-NATO interactions in the field of countering hybrid threats. This research identifies three key findings. First, the shift in the international security environment following Russia’s 2014 invasion of Crimea was instrumental in prompting both the EU and NATO to prioritise countering hybrid threats, leading to functional overlap. Second, this overlap fostered cooperation rather than conflict, as both organisations recognised their mutual reliance on one another’s resources to address hybrid threats effectively. Third, Hybrid CoE played a critical role in managing and supporting the EU-NATO functional cooperation by increasing the frequency and depth of interactions between the two organisations and by enhancing informal relations. These findings highlight the significance of exogenous shocks, resource-driven cooperation, and informal relations in fostering EU-NATO cooperation in the realm of countering hybrid threats.