The EU has been confronted with mounting challenges in the pursuit of its foreign and security policy. The distribution of power amongst multiple players – from the United States to Russia and China, but also regional players like Iran or Turkey – that espouse conflicting views of order compels the EU and its member states to rethink their international engagements along multipolar patterns. The severe weakening of state authority and governance mechanisms in regions across the EU’s borders fuels a multiplicity of challenges, from illicit trafficking to migration flows, which the EU struggles to address simultaneously and organically. These systemic phenomena intermingle with internal divisions across member states to further complicate EU efforts to deal with the many crises and conflicts that impinge on Europe’s security. Multipolar competition, regional fragmentation and internal contestation, individually and in combination with one another, define the context of EU foreign and security policy. In this study, we explore how the EU dealt with crises and conflicts between the mid-2000s and the early 2020s – including Russia’s invasions of Ukraine, Iran’s nuclear dispute, Syria’s civil war and others still – to understand the peculiar nature of the EU’s role in international security. We argue that the EU is a ‘relational power’, an entity dynamically constituted by its interaction with its internal and domestic context. As such, the EU emerges as collective actor that amplifies its member states’ international influence but is not capable of engaging in power contests on its own. We also offer policy-relevant insights into future scenarios of reform or fracture of EU foreign and security policy.