The idea of a European army has been discussed, proposed, shelved and revived so many times that it has acquired almost mythological status in EU politics — always just over the horizon, perpetually postponed by the obstacles of national sovereignty and NATO’s continued existence. Yet the conversation in 2026 looks genuinely different from what it looked like five years ago. The war in Ukraine, the uncertainty around American security commitments, and the massive ramp-up in European defence spending have created conditions in which structural defence integration is no longer purely theoretical. But the obstacles remain real, and the path from aspiration to capability is not short.
1950: The first attempt — and its failure
The European Defence Community was proposed in 1950 — barely five years after the end of World War Two — as a framework for rearming West Germany within a supranational European military structure. The treaty was signed by six countries in 1952. The French National Assembly rejected it in 1954, ending the first serious attempt at European military integration before it could begin. The lesson absorbed by the EU’s founders was that defence was too close to the sovereign core of nationhood to be pooled in the same way as trade or agriculture.
1999–2007: CSDP and its structural limits
The Kosovo crisis of 1999, and European militaries’ dependence on American assets to conduct operations in their own neighbourhood, catalysed the creation of the EU’s Common Security and Defence Policy. Between 1999 and 2007, the EU established a series of institutional structures — the Political and Security Committee, the EU Military Committee, the European Defence Agency — and began conducting civilian and military missions. These missions, in the Balkans, Africa and the Middle East, demonstrated that EU member states could cooperate militarily. They also demonstrated the limits: all missions were voluntary, all operations depended on national contributions, and NATO remained the primary framework for collective defence.
2016–2021: PESCO and the defence union ambition
The twin shocks of Brexit and Donald Trump’s first election triggered a new push for European strategic autonomy. Permanent Structured Cooperation (PESCO) was launched in 2017, allowing willing member states to cooperate on specific defence capability projects within the EU framework. By 2021, over 60 PESCO projects were underway, covering everything from military mobility to cyber capabilities to field hospitals. The European Defence Fund, providing EU budget money for collaborative defence R&D for the first time in the EU’s history, accompanied this wave.
2022–2026: Ukraine changes the calculus
The full-scale invasion of Ukraine in February 2022 transformed the political environment for European defence integration more fundamentally than any previous event. The EU used Article 10a of the European Peace Facility — an off-budget instrument — to reimburse member states for weapons deliveries to Ukraine, taking an unprecedented role in military supply chain coordination. The European Defence Industrial Strategy, published in 2024, called for 40% of defence equipment to be procured jointly by 2030 and for 35% of military goods to be traded within the EU by 2030. As detailed in our European rearmament analysis and air defence assessment, the gap between European aspiration and industrial reality remains significant — but the direction of travel has shifted.
What a common defence force would actually require
A genuine EU defence capability — as opposed to coordinated national capabilities operating under an EU label — would require common command structures, integrated logistics, shared procurement, and — the hardest part — a political agreement on when and how to use force. That last requirement means common foreign policy, which as our editorial on European foreign policy argued, remains the deepest unresolved challenge. Military integration without political integration is logistics. Genuine European defence autonomy requires both.
