Leaders and followers in European Defence: Insights from Capability Coalitions for Ukraine

The traditional model of leadership in European defence is undergoing profound transformation. The long-standing ‘layered’ structure – where the United States served as NATO’s permanent security guarantor, the Franco-German axis acted as Europe’s regional leader, and the European Union played a supporting role – is giving way to a more fluid and contested landscape. The gradual withdrawal of the US, the re-engagement of Global Britain in European security, challenges to Franco-German leadership, the rise of new subregional groupings, and the proliferation of bilateral defence partnerships all signal a shift in Europe’s strategic order. At the same time, tensions are intensifying between member states seeking to retain control and the European Commission pursuing a more assertive defence and geopolitical agenda. These developments are paralleled by a broader global trend toward informal, coalition-based forms of cooperation, moving away from traditional multilateral institutions toward flexible arrangements among likeminded partners. Together, these dynamics raise a central question: who leads Europe’s defence in this emerging order? This paper takes a first step toward answering that question by mapping European contributions to the eight Capability Coalitions established within the Ukraine Defence Contact Group. After a descriptive analysis of coalition membership, it identifies patterns of participation and leadership among European states. By doing so, the paper contributes to the developing literature on informal and ad hoc governance in European security and generates new empirical insights into leadership dynamics in European defence.