Beyond Consensus: Complementarity as EU Conflict Management in Foreign Policy Crises

The dominant debate in EU foreign and security policy treats the EU’s action on the global stage as binary: it either speaks with one voice or it fragments into competing national positions. This framing obscures the ever more visible reality that unity and consensus are not synonymous, nor are they the only enablers of EU external action. This paper introduces a theoretical framework that positions EU unity not as the absence of internal conflict, but as the product of how such conflict is managed. The central insight here is that successful cooperation does not require MS to converge on preferences or achieve formal consensus. Instead, what varies across combinations of external pressures for and internal costs to act collectively is the mode and intensity of conflict management, which produces different patterns of complementarity. Complementarity - understood here as the degree to which the actions of EU supranational institutions and Member States reinforce rather than contradict each other politically, strategically and operationally - is not uniformity. It allows the EU to escape consensus paralysis by permitting differentiated action, managing rather than resolving internal conflict through flexible coordination, and preserving strategic and operational convergence even when political agreement is incomplete. This bestows on the EU the capacity to assume different forms as a global actor, from scattered to unitary through pluralist. The paper then traces how complementarity emerged in the EU’s initial response to Russia’s 2022 invasion of Ukraine, where the Union demonstrated remarkable unity despite lacking full consensus on military support. It examines how the combination of external demand for a united front and internal costs of disjointed action created incentives for Member States and institutions to develop flexible arrangements that preserved functional collective action without requiring unanimous agreement on all actions. This case contributes to understanding current developments in European security by revealing that EU action and actorness in crisis response depend less on achieving formal and unanimous agreement than on managing conflict through complementary pluralism.