European security has rarely looked more precarious. To the continent’s east, Russia continues to wage its war on Ukraine and test European sovereignty with everything from airspace incursions to disinformation campaigns. Even a ceasefire would not change the underlying reality: a revisionist Russia is intent on establishing a sphere of influence backed by a military buffer zone across central and eastern Europe. In other words, Europe is the number one target. A limited Russian attack on allied territory, met with a divided or hesitant response, could alone be enough to erode confidence in the mutual defence commitments that Europe’s security rests on—and with it, the political project they protect.
Meanwhile, to Europe’s west, US president Donald Trump has been unusually consistent in signalling that America is done guaranteeing Europe’s security and has shown little appetite for confronting Russia. In practice, NATO remains the backbone of European security and America still provides the bulk of the alliance’s operational strength: roughly 75,000 US troops are still stationed across Europe (even though this number seems to change by the day) and the Supreme Allied Commander Europe (SACEUR), NATO’s top military leader, is American. Politically, however, Europeans find themselves in a world where American willingness to uphold security guarantees is frail at best. What to many seemed like heresy in summer 2024—preparing to defend Europe with less America—has become necessity.
Europeans thus face a kind of “Schrödinger’s NATO”: the US appears both committed to, and absent from, the alliance at the same time. Instead of keeping NATO fully reliant on America and risk finding it dead in their hour of need, Europeans need to create a security architecture underpinned by Europeans themselves.
This paper sketches out a plan for Europe to confront the possibility of American abandonment head-on within the critical 5 to 7 year window in which the risk of Russian aggression is highest. The goal is not to replicate America’s role in Europe, but to develop a distinctly European model of defence that builds on NATO’s structures but can function with little to no US participation.
This plan rests on three pillars. First, Europeans need to work with, not against, their institutional fragmentation through a structure of interoperability. This requires an agile system in which NATO frameworks, EU instruments and flexible coalitions cooperate effectively. Rather than trying to redesign institutions, the short-term priority should be to better connect existing tools and ensure they work even if there are delays or blockages in triggering Article 5, NATO’s mutual defence clause. Second, Europeans need to build better military capabilities and enough rapidly deployable, combat-ready forces, otherwise any newly established European defence model will be nothing more than a paper tiger. And third, this will need to be supported by a strong, home-grown military industrial and technological backbone. A European way of deterrence and defence—coalition-based, flexible and rooted in mutually reinforcing NATO and EU structures—would allow Europeans to generate military power without depending on American goodwill.
To keep their continent safe, Europeans must build their ability to act with America where possible, with less America where necessary and without America if it comes to that. And they need this plan to be ready immediately in the case of aggression, not after weeks of political deliberation. This paper sets out how Europeans can do so—deterring Russia and ensuring that no country under attack would have to fight alone, whether or not Article 5 holds.
About the authors
Rafael Loss is a policy fellow at the European Council on Foreign Relations.
Marta Prochwicz Jazowska is the deputy head of the Warsaw office and a policy fellow at ECFR.
Dr Jana Puglierin is a senior policy fellow at the European Council on Foreign Relations and head of its Berlin office since January 2020.