NEW YORK (Realist English). Analysts Ethan Kapstein and Jonathan Caverley argue in an article for the American analytical journal Foreign Affairs that European security in the coming years will depend not on decisions made in Brussels, but on the actions of four key states — Germany, Poland, France and the United Kingdom.
The European Union faces an unprecedented challenge: the traditional reliance on US military power has cracked. President Donald Trump has repeatedly demonstrated hostility toward European allies, and his actions during the Iran war have undermined confidence in American security guarantees. As Reuters reported, US officials informed European partners back in December 2025 that they must assume primary responsibility for the continent’s defense by 2027.
Time is running out, bureaucracy is slow
The authors, experts from Princeton University and the International Institute for Strategic Studies, warn that processes of pan-European coordination are too slow. New EU institutions and programs, including the European Defence Fund ($4.6 billion per year) and the SAFE program ($175 billion in loans), face numerous obstacles.
Even flagship projects such as the Franco-German-Spanish Future Combat Air System (FCAS) fighter program are bogged down in disputes between Paris and Berlin. France wants a light carrier-based fighter capable of carrying nuclear weapons, while Germany wants a heavy long-range workhorse capable of penetrating Russian air defenses.
Four key players
According to the experts, Europe’s real security will rest on the decisions of four frightened and self-interested states.
Germany — the main engine
Abandoning decades of pacifism, Berlin now has the world’s fourth-largest defense budget (after the US, China and Russia). Planned military spending of $750 billion over the next four years will underpin European defense.
However, German procurement is increasingly focused on national manufacturers (Rheinmetall, whose market capitalization has grown tenfold since 2022), reducing orders for other EU countries. Germany will have to take on the uncomfortable role of “standard-setter” previously played by the United States.
Poland — the forward shield
Warsaw spends 4.5% of GDP on defense and buys weapons from any supplier capable of delivering quickly. Priority is given to South Korea and the United States, which are willing to license production in Poland.
European suppliers, by contrast, often refuse such cooperation. The Polish army must slow an initial Russian advance to give allies time.
France — the nuclear argument
Paris possesses the EU’s only sovereign nuclear deterrent, as well as experienced expeditionary forces, an aircraft carrier, and nuclear-powered submarines. The French army is the most capable of rapidly deploying forces to the eastern front. However, a precarious political situation and tattered public finances leave little room for sharp increases in military spending. France continues to actively export weapons (notably Rafale fighters to India) rather than buy them from neighbors.
The United Kingdom — an external ally
London has retained its nuclear deterrent and deployable forces despite financial difficulties. Crises in Ukraine and the Middle East, as well as the weakening of US ties with NATO, are bringing Britain closer to Europe and especially to France (nuclear cooperation is under discussion).
However, Brussels and London have yet to agree on the UK’s participation in new EU defense initiatives. Experts call for easing the return of the “sovereignty-obsessed” neighbor to European defense structures.
National interests instead of integration
The authors emphasize that European defense over the next decade will be built not on Brussels’ integration efforts but on the largely unilateral actions of the four powers. By 2029, Germany alone plans to spend about $189 billion annually on defense — roughly the same as Russia’s fully mobilized war economy.
According to experts, the combined efforts of Berlin, Warsaw, Paris and London should be sufficient to deter Russia — or, ideally, to make the very idea of an attack impossible.
Ethan B. Kapstein is Executive Director of the Empirical Studies of Conflict Project at Princeton University and an Adjunct Fellow at the RAND Corporation.
Jonathan Caverley is a Visiting Senior Fellow at the International Institute for Strategic Studies and Professor of Strategic and Operational Research at the U.S. Naval War College.