EU‑US defence cooperation

Introduction

The security and defence relationship between the EU and the United States (US) has long been central to European security.Through NATO, Washington has (since NATO's establishment) provided key military capabilities and security guarantees that remain indispensable for most EU Member States. This is particularly the case regarding Europe's reliance on American strategic enablers, such as 'intelligence, surveillance, and reconnaissance' (ISR), battlefield command and control, air‑to‑air refuelling, as well as strategic airlift and long‑range strike capabilities.

EU‑US defence cooperation has developed through political agreements and operational initiatives since the early 2000s. A 2011 framework agreement enabled US participation in EU crisis management operations, while subsequent arrangements between the European Union Military Staff and US European Command strengthened information exchange and coordination. The 2014 EU-US Summit Declaration further reaffirmed joint crisis management efforts.

After limited engagement during Trump's first administration, cooperation regained momentum under President Biden. The US joined the Permanent Structured Cooperation project on military mobility, and the 2021 EU‑US Summit also launched a dedicated security and defence dialogue, and paved the way for an administrative arrangement between the European Defence Agency and the US Department of Defence, finalised in 2023. Russia's full‑scale invasion of Ukraine in 2022 further intensified transatlantic coordination, including reinforced US deployments in Europe, cooperation on energy security, and coordination on export controls through the EU-US Trade and Technology Council. Operational cooperation also expanded through joint exercises in 2023 and 2024.

Donald Trump's return to the White House in 2025 renewed uncertainty among US allies regarding the future direction of American defence and alliance policy. Diverging messages from the White House and other US institutions – especially on Greenland – have raised concerns about the coherence and reliability of US commitments to European security.

Trump's second presidency

Transatlantic tensions intensified in 2025, as President Trump pressed for US control of Greenland, initially refusing to rule out force, while his Vice President, JD Vance, sharply criticised European governments at the Munich Security Conference. Trump later ruled out force, reaching a security agreement with Denmark and Greenland, and Secretary of State Marco Rubio adopted a more conciliatory tone at the Munich Security Conference in 2026. However, concerns persist over the reliability of US security guarantees amid conditional commitments, domestic polarisation, economic tensions and strategic retrenchment.

Ukraine has also remained central to transatlantic security debates, naturally even more so in Europe. Washington indicated that any future peacekeeping mission in Ukraine would involve European and other partners, rather than US troops, and would operate outside the framework of NATO's Article 5 guarantee. Divergences have also emerged between the American and European approaches to a potential settlement concerning the war. European proposals emphasise strong US security guarantees and involvement in ceasefire monitoring, while the American plan envisages guarantees provided primarily by European and other partner countries. These developments have raised concerns among European leaders about the US's role in negotiations affecting European security. In February 2025, the Weimar+ group, including France, Germany, Poland, Spain, the United Kingdom and the EU's High Representative (HR/VP), stressed that both Ukraine and Europe must be involved in any peace process. Talks in Geneva in February 2026 between Russia, Ukraine and the US produced limited progress on military arrangements, but failed to resolve fundamental political disputes. Kyiv insists on a comprehensive ceasefire before negotiations on a political settlement, while Moscow continues to demand control of the entire Donbas region.

In September 2026, US envoys Steve Witkoff and Jared Kushner met President Putin in Moscow and President Zelenskyy in Kyiv, in an effort to revive stalled US‑mediated peace talks. Meanwhile, Russia temporarily halted strikes on Kyiv, but maintained its territorial demands and attacks elsewhere in Ukraine, with no apparent breakthrough. President Trump separately decided to grant Ukraine licences to produce Patriot air‑defence missiles domestically, according to President Zelenskyy.

According to expert assessments, Washington's argument that Russia is negotiating in good faith has increased pressure on Zelenskyy to reach an agreement, prompting European governments to intensify their support for Ukraine. According to analysts, the US's reduced military footprint and ambiguous political signalling may be interpreted by adversaries as an opportunity to test the unity of the NATO alliance. Statements concerning Greenland added to these strains, raising concerns about respect for sovereignty within the alliance itself. These developments do not imply an imminent rupture. They do, however, underscore the need for European governments to reassess assumptions about US reliability and to strengthen their own capacity to act, should transatlantic solidarity weaken.

The 2025 National Security Strategy and 2026 National Defense Strategy

The 2025 National Security Strategy breaks with the post‑1945 consensus that sustained global primacy serves US interests. Instead, it promotes a narrower conception of national interest, prioritising sovereign nation states, reducing commitments seen as unrelated to core US objectives, and adopting a more critical stance towards international institutions. While not isolationist, the strategy puts emphasis on unilateral economic and military power and adopts a more openly partisan tone than previous strategies. The document reorganises regional priorities by placing the Western Hemisphere first, followed by Asia and Europe. It proposes a renewed Monroe Doctrine (the doctrine, introduced by US President James Monroe in 1823, established the principle that the US would oppose interference by foreign powers, particularly European states, in the Western Hemisphere), aimed at limiting external influence, particularly from China. The strategy calls for greater European responsibility for defence; an end to the perception that NATO is engaged in continuous enlargement, and a restoration of 'strategic stability' with Russia. It also adopts a notably critical tone towards Europe's political and societal trajectory, while continuing to describe the continent as strategically indispensable to the US.

An expert from the Foreign Policy Research Institute argues that the strategy does not signal a US withdrawal from Europe, but reflects concerns that political and demographic trends could weaken transatlantic cohesion and democratic legitimacy. Experts from the European Council on Foreign Relations contend that the strategy places Europe in an asymmetric geo‑economic relationship, that advances US interests while undermining European cohesion and strategic autonomy. An analyst from the Center for Strategic and International Studies argues that the strategy formalises a transactional 'America First' approach, by expecting Europe to assume greater responsibility for its own security while risking deeper transatlantic divisions.

The 2026 National Defense Strategy (NDS) argues that when President Trump began his second term in January 2025, the United States stood at the 'precipice of a world war', confronted by escalating threats across multiple regions. Domestically, the document portrays severe pressure at the southern border and rising cartel‑related threats throughout the Western Hemisphere. It also raises concerns about potential uncertainty over US access to strategic locations such as the Panama Canal and Greenland. The strategy also argues that China's growing military power in the Indo‑Pacific increasingly threatens US security, while European allies should assume greater responsibility for supporting Ukraine and deterring Russia. It identifies Iran as the main threat in the Middle East and acknowledges North Korea's nuclear threat to South Korea and Japan. In response, the strategy prioritises defending the US by deterring China, increasing allied burden‑sharing and strengthening the US defence industrial base, framed within an approach of 'flexible realism', focused on restoring a 'warrior ethos' rather than defending a rules‑based international order.

A Stimson Center expert argues that the NDS risks undermining its own priorities by rank‑ordering threats while implying the US can address multiple challenges simultaneously. The same report questions the emphasis on burden‑sharing with Europe, without clarifying the consequences if allies fail to meet expectations. By contrast, one Atlantic Council expert argues that the strategy's strength lies precisely in clearly defining priorities and avoiding earlier patterns of strategic overstretch. Another affiliated analyst contends that the strategy remains underdeveloped, providing limited guidance on how priorities translate into operational plans and warning that its transactional approach to alliances may ultimately increase strategic risks.

Regarding Europe, the 2026 NDS calls for European NATO allies to assume primary responsibility for their conventional defence, with 'critical but more limited' US support. It argues that longstanding allied reliance on US protection has placed a disproportionate burden on Washington, while emphasising that greater burden‑sharing is essential to strengthening deterrence. The strategy also adopts a more conditional approach to defence cooperation, prioritising 'model allies' that meet defence spending expectations and contribute more actively to regional security. Such allies would receive preferential consideration for cooperation in areas including defence industrial collaboration and intelligence‑sharing.

In February 2025, US Secretary of Defence Pete Hegseth warned that European allies could no longer assume that there will be a permanent American military presence in Europe. At present, more than 80 000 US troops remain stationed across Europe, including roughly 38 700 in Germany. While the Trump administration has signalled plans to reduce its military footprint, it has called for greater European responsibility within NATO rather than a large‑scale withdrawal. In May 2026, Trump announced the withdrawal of 5 000 US troops from Germany and cancelled planned Tomahawk missile deployments (see below). NATO commander Alexus Grynkewich stated that US force reductions would be gradual and accompanied by continued American support in key areas such as intelligence, command systems, and nuclear deterrence.

Russia is described in the NDS as a persistent, but manageable, threat to NATO's eastern members. The NDS argues that European NATO members collectively exceed Russia's economic and demographic capacity, and that Moscow therefore lacks the ability to achieve continental hegemony, even though it can sustain prolonged conflict in its neighbourhood. If allies meet the spending commitments agreed at the 2025 ATO summit in The Hague, including a target of 5 % of GDP on defence and security by 2035 (with 3.5 % devoted to core military capabilities), the strategy argues they would be well positioned to assume primary responsibility for Europe's conventional defence. The document reiterates President Trump's view that the war in Ukraine must end and frames responsibility for supporting Ukraine and sustaining any settlement primarily as a European task. At the same time, the strategy notes that Russia continues to threaten the US through its large and modernising nuclear arsenal, as well as through its capabilities in the undersea, space and cyber domains. Although Europe remains strategically important, the NDS observes that its share of global economic power is declining. The US therefore places priority on national defence and deterrence of China, while maintaining its role within NATO and its continued engagement in Europe.

A European Policy Centre expert argues that the new US NDS reflects a shift towards a 'Fortress America' posture, reducing Europe's centrality in US strategy and forcing Europeans to choose between rapidly strengthening their own military capabilities, or accepting greater strategic risk under a more conditional US security guarantee. An expert from the Egmont Institute sees the strategy as a recalibration rather than a withdrawal from NATO. While the US remains engaged, it expects European allies to assume a larger share of the conventional defence burden, reinforcing the need for stronger European deterrence and greater strategic autonomy in an increasingly uncertain transatlantic security environment.

EU‑US defence industrial relations

After 1945, the US established a defence cooperation system that preserved the primacy of its domestic defence industrial base while allowing selective collaboration with allies. Production remained centred on the US and was largely organised through bilateral arms transfers. Export control regimes, particularly the International Traffic in Arms Regulations (ITAR) and the Export Administration Regulations, restrict the re‑export of US technology and limit deeper industrial integration among allies. Transatlantic defence relations therefore remain dominated by bilateral arrangements and reinforced by 'Buy American' provisions, with only limited exemptions.

Foreign military sales and direct commercial sales have anchored long term industrial links between the US and European allies. Despite this, European access to the US defence market remains limited. The number of arms imports by European members of NATO highlights the overall dependence on the US: the Financial Times notes that 'almost two thirds of the arms imported…over the past five years were produced by the US'. In December 2025, NATO allies and partners pledged over US$4 billion in US‑sourced military equipment and munitions for Ukraine through the Prioritised Ukraine Requirements List (PURL), with contributions increasing since August 2025; this trend is expected to continue. The current war in Iran has led to fears by US allies that it will leave them without US weapons they bought or that their delivery will be delayed, as these are being depleted in Iran instead.

Transatlantic co‑production has strengthened industrial ties in aerospace and missile programmes. The F‑35  programme illustrates this model. Managed entirely by the US Department of War, it invited selected allies to contribute financially, in return for industrial workshare opportunities. European participants, including Belgium, Denmark, Italy, the Netherlands and the United Kingdom, benefited economically but faced strict limits on technology transfers. In other words, programme governance and technological development remained firmly under US control, reflecting the overarching asymmetric structure of transatlantic armaments cooperation.

Export control regimes shape most industrial interactions. US rules administered through ITAR regulate technology transfers, brokering and re‑exports of defence items; frequently affecting European programmes that include US components. European responses have included licensing arrangements and efforts to develop ITAR‑light or ITAR‑free systems, with the purpose of preserving export flexibility and operational autonomy. The Eurodrone programme, for example, was deliberately designed to minimise US‑controlled components, so that export licensing remains under European authority. Transatlantic defence industrial issues are addressed through institutional frameworks including the EU‑US security and defence dialogue, the EU‑US Trade and Technology Council and NATO initiatives aimed at strengthening defence production and innovation networks.

Capabilities

Russia's war against Ukraine has exposed Europe's heavy dependence on US strategic enablers. Analysts warn that European deterrence would be severely weakened if the US reduces its support, particularly given Europe's limited satellite infrastructure and currently fragmented defence planning. Europe also remains reliant on the US nuclear umbrella, including forward‑deployed American nuclear weapons in several European NATO states and US strategic nuclear forces, which continue to underpin the credibility of NATO's nuclear deterrence. While some capabilities, such as aerial refuelling and strategic airlift, have improved through platforms like the Airbus A330 MRTT and A400M, experts estimate that replacing key US enablers would require at least five to ten years of sustained investment and political coordination.

In response to a deteriorating security environment, the EU has intensified efforts to strengthen its defence readiness and capability development. In October 2025, the European Council reaffirmed the objective of enhancing the Union's defence readiness by 2030, reflecting a growing political consensus that the EU must assume greater responsibility for its own security as global security dynamics evolve and the engagement of key partners becomes less certain.

In March 2025, the European Commission and the HR/VP launched the White Paper for European Defence: Readiness 2030 and the ReArm Europe Plan to increase defence investment and address critical capability gaps. The subsequent readiness roadmap identified priority areas including air and missile defence, drones, cyber, artificial intelligence, military mobility and strategic enablers such as space and critical infrastructure protection. The EU also introduced annual capability assessments linked to the Coordinated Annual Review on Defence (CARD), to align procurement priorities and strengthen collaborative defence planning. To address persistent shortfalls and low levels of joint procurement, Member States are expected to cooperate through capability coalitions supported by EU institutions. In parallel, the Commission proposed several flagship initiatives, including a European drone defence initiative, a European air shield and a European space shield. This has caused controversy as some Member States favour maintaining such initiatives primarily at national, NATO or intergovernmental level. Therefore, the European Council of 23 October 2025 did not endorse the European Commission roadmap for the Readiness 2030 plan and instead emphasised a stronger role for the European Defence Agency, illustrating Member States' preference for intergovernmental mechanisms in defence cooperation.

In September 2026, Member States endorsed the first five European Defence Projects of Common Interest (EDPCIs). EDPCIs aim to address critical capability gaps. Established under the €1.5 billion EDIP, the projects focus on five priority areas: drones and counter‑drone systems, maritime and seabed defence, space, air and missile defence, and the EU's eastern flank. The Commission has earmarked €325 million to support their establishment. On average, 18 Member States participate in each project, with Ukraine involved in four of the five.

European Parliament position

The European Parliament's 2025 report on common security and defence policy (CSDP) implementation reaffirmed that the US remains the EU's most important strategic ally and a central pillar of NATO and European security. However, it criticised the December 2025 US National Security Strategy for reflecting a more transactional approach towards allies, warning that growing unpredictability, isolationist tendencies and shifting US priorities could reduce American military commitments to Europe. Parliament argued that the EU and its Member States should strengthen their own defence capabilities and readiness, while preserving a balanced transatlantic partnership. In a separate resolution on EU strategic defence and security partnerships, Parliament reiterated that the EU‑US relationship remains a cornerstone of European security and called for deeper cooperation. It also stressed that strengthened European defence would reinforce both NATO and transatlantic security, amid uncertainty over future US commitments.