Complementarity between the EU and NATO in light of the war in Ukraine: an analysis from the perspective of collective securitization theory

Although the majority of studies on collective securitization theory (CST) focus primarily on states as the principal actors, certain scholars also concede the potential occurrence of collective securitization within international organizations. Aligned with this viewpoint, the present article posits that CST framework can serve as a valuable tool in substantiating the commonly voiced notion of complementarity between NATO and EU. With this purpose, specific focus is placed on Russia's war in Ukraine that has been unfolding since February 2022. Hence, all six stages of CST have been taken into consideration to justify the assumption that CST is applicable as an analytical framework to elucidate such complementarity.