This paper explores the challenges of the European Union (EU) in developing a common strategic culture and, consequently, a coherent political autonomy on the international stage. By examining the evolution of the Union’s security narratives and the challenges these pose to its political autonomy, particularly in light of the war in Ukraine, the paper highlights that certain institutional mechanisms of intergovernmental nature and the discordance between the strategic interests of member states hinder the development of a collective European position. These challenges widen the capability-expectation gap of the EU and affect military coordination. In this regard, the lack of a common strategic culture also has an impact on the interoperability of military capabilities, as the varied priorities and defence strategies of member states complicate efforts to harmonise doctrines across the EU.