The role of European leaders in shaping the European defence agenda

This paper investigates how European leaders are shaping the EU’s defence agenda by situating their actions within what Matthijs (2024) defined as Europe’s emerging 'leadership void'. Drawing on leadership studies, agenda-setting theory, and multilevel governance, it examines how key figures—including Commission President von der Leyen, European Council President Costa, French President Macron, German Chancellor Merz, Italian Prime Minister Giorgia Meloni, and UK Prime Minister Starmer—sought to fill this void through problem framing, coalition building, and the strategic use of institutional venues. The analysis shows how leaders operating at different levels of governance—and increasingly through overlapping, flexible, and informal formats—interacted to prioritise defence, industrial capacity, and Ukraine-related commitments. It demonstrates how the 2025 US National Security Strategy, with its emphasis on allied burden-sharing, deterrence, and the need for Europeans to assume greater responsibility for their own security, reshaped opportunity structures for EU leaders and elevated defence cooperation as a core European task. By analysing how individual leadership styles, resources, and multilevel interactions shaped Europe’s collective positioning during the second Trump administration, the paper illustrates how Europe’s evolving defence agenda emerged not only from structural pressures but also from leader-driven attempts to navigate an increasingly complex transatlantic scenario.