From Pax Americana to Pax Europaea: Can Europe Defend Itself?

Last September, French President Emmanuel Macron and British Prime Minister Keir Starmer co-chaired the “Coalition of the Willing,” aimed at safeguarding Ukraine’s security amid the Russia–Ukraine war. By the end of the summit, a total of 26 countries, including France, the UK, Poland, Germany, and Italy, pledged to deploy troops in Ukraine “on the ground, at sea, or in the air.” Beyond Ukraine, Starmer described the moment as a “once in a generation” opportunity for a European shared security and defence framework long held back by collective action issues.

Russia is widely suspected of being behind a series of drone intrusions into European airspace, including incidents over Poland, Estonia, and Denmark. These incursions have reinforced concerns that European states must act collectively against the Russian threat. Ukrainian President Volodymyr Zelenskyy has warned that Ukraine lacks enough missiles to intercept the full range of drones used by Russia. Danish intelligence services have urged the EU to pursue a major rearmament program, arguing that Russia could be capable of launching a large-scale war in Europe if NATO were weakened. In response, the EU approved a €150-billion loan program to finance weapons purchases through 2030.

This shift has been accelerated by Donald Trump’s posture toward Europe. Stéphane Séjourné, Executive Vice-President for Prosperity and Industrial Strategy at the European Commission, has said that Trump treats Europe as “just one continent among others” rather than a privileged ally. Public opinion reflects this concern: 63 per cent of Europeans say Trump’s presidency has made the world less safe, and 51 per cent view him as an enemy of Europe. These perceptions have lowered expectations of US protection and have pushed the EU toward greater strategic autonomy. Rather than relying on external guarantees, the Union is increasingly seeking to take responsibility for its own security through a pan-European defence framework based on pooled resources and joint action.

Europe has not remained passive as Trump publicly snubbed the Ukrainian president, threatened transatlantic trade, supported Europe’s far right, and even questioned Greenland’s sovereignty. As a result, momentum has grown behind a pan-European defence project—one in which EU member states act collectively rather than relying on external security guarantees.

There is evidence of public support for EU-level defence integration across member states. 77 per cent of EU citizens support a common defence and security policy within the EU, and 80 per cent believe defence cooperation should be increased. These surveys reflect what the Commissioner for Defence and Space, Andrius Kubilius, has called “Pax Europaea”: Europe taking more responsibility for its own security, strengthening deterrence, and upholding democratic values.

There are many reasons why the EU may seek to endow itself with a defence and security alliance. However, significant obstacles remain.

A strong and independent defence union would require “abandoning a certain naivety and not blindly relying on US support,” according to Séjourné. While Trump’s posture toward Europe has united many EU member states, pan-European defence goals may not be entirely realistic. German representatives have said they do not want to “give the impression” that Germany seeks “to decouple [itself] from the US”—and for good reason. Nearly half of Europe’s active fighter jets are US-made, and American missile-defence systems are the most widely deployed across the continent. Among Europe’s most prominent national actors, only France purchases more equipment from European partners, while the rest rely on the United States. The American F-35 Lightning II outcompetes its European contenders, and the Eurofighter Typhoon and the French-made Rafale account for far smaller shares of aircraft in European militaries. This reflects not only a lack of technological autonomy, but also an absence of the pooled resources required for a pan-European defence system. Insufficient funding has been channelled into a common project, as political coordination on defence matters remains difficult. Moreover, European economies are relatively minor, and many available resources are allocated toward NATO spending, in line with Trump’s demands.

There is a significant trade-off between allocating resources to NATO efforts and investing in a pan-European defence system. EU member states have maintained that national defence priorities should not be “in competition” with NATO, as Kubilius has said. Some member states’ domestic security measures are designed to support NATO initiatives. For example, the eastern European flank depends heavily on NATO’s Article 5 to safeguard sovereignty, reinforcing NATO’s security primacy in the region. While the EU and NATO share similar approaches to China and Russia, significant divergence may emerge between the United States and the EU’s foreign policy objectives. 23 of the EU’s 27 member states are also NATO members. In the context of a pan-European defence system, this overlap could create competing obligations. States bound by both frameworks may struggle to meet commitments to each, or may pursue conflicting actions, fracturing institutional cohesion. As a result, the EU–NATO relationship remains a “double-edged sword” if capacities and responsibilities are not clearly defined.

Finally, the European constitutional framework poses a significant obstacle. Article 4(2) of the Treaty on European Union (TEU) provides that national security remains the responsibility of each member state. At the same time, the Common Security and Defence Policy (CSDP) requires unanimity in the European Council. While Article 2(4) TEU recognizes that the Union may progressively develop a standard defence policy, it does not grant exclusive or shared competence that overrides national authority. As a result, tensions arise when the Commission encourages defence initiatives requiring deep coordination. Such initiatives often involve sovereignty trade-offs, requiring binding commitments that limit unilateral discretion. Consequently, a single objection can block action and stall momentum.

An inherent conflict, therefore, exists between Europe’s constitutional framework and current political realities. On the one hand, the Union must overcome unanimity requirements and the CSDP’s limited powers; on the other, Russia’s war, drone attacks, missile threats, and uncertainty surrounding US security guarantees require sustained investment and coordination. Despite strong support for a pan-European defence system, constitutional constraints and political interests continue to limit progress. As a result, ad hoc coalitions and national initiatives have become the default response, bypassing the EU’s formal defence architecture and undermining the long-term goal of a unified European defence policy. The “Coalition of the Willing” addresses immediate security needs: EU members prioritize deterrence against Russia in the short term, while institutional barriers continue to block the development of a comprehensive EU defence strategy.

Edited by Allison Dera

Featured image:  “Securing Our Future London Summit participants on 2 March 2025” by Christophe Licoppe is licensed under CC BY 4.0.