Imagining a Post-American Europe: The Future of Europe’s Deterrence Architecture

The Trump administration has thrown Europe into a tailspin. In his first 100 days in office, Washington has pulled the plug on Ukraine, tried to accommodate Russia, waged a tariff war against the European Union (EU) and warned that Europe’s greatest threat comes from within, accusing its leaders of suppressing free speech and failing to halt illegal migration and cultural degeneration. Many now question the wisdom of taking America’s commitment to European defence for granted. Against this backdrop, reports that the Pentagon was allegedly contemplating relinquishing its long-held role as Supreme Allied Commander Europe (SACEUR) sent shockwaves across Europe.

Of course, the future of United States (US) military engagement is anything but decided. During his first visit to Europe, US Secretary of Defense Pete Hegseth affirmed that America remains committed to NATO, yet adding that ‘European allies must lead from the front’ and ‘take ownership of conventional security of the continent’. A leaked internal guidance memo from the Pentagon more recently suggested that the US would continue to support Europe with nuclear deterrence but ‘is unlikely to provide any substantial, if any, support to Europe in the case of Russian military advances’.

In light of an uncertain and ambiguous American role in transatlantic security, Europe’s political and military leaders will need to consider various scenarios for their continent’s future security architecture, ranging from minor downward adjustments in US military engagement to a full-fledged American withdrawal – and the many different shades in between these two extremes. Each potential future presents Europeans with different questions, dilemma’s and trade-offs: what it would require in terms of Europe’s conventional build-up; how it would affect command and control arrangements; and what it means for US extended nuclear deterrence. What is more, Europe’s future security architecture will be shaped by broader geopolitical developments such as US-China competition in the Indo-Pacific or the speed and depth of Russia’s military reconstitution.

To reflect on the shape and future of Europe’s deterrence architecture, the Centre for Security, Diplomacy and Strategy (CSDS) is launching a new initiative on the “Future European Deterrence Architecture” on Wednesday 14 May at 15:00 – 16:15 at the Press Club in Brussels. For the event, the CSDS team will be joined by Gideon Rose, Adjunct Senior Fellow at the Council on Foreign Relations and former editor of Foreign Affairs, and Tomasz Szatkowski, former Ambassador of Poland to NATO and former Deputy Minister of National Defence.

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