This commentary is part of the European Leadership Network’s special coverage of the 2026 NATO Summit, which will take place in Ankara on 7-8 July 2026. The series brings together expert voices to examine the key security challenges, strategic questions, and policy debates shaping the future of the alliance before and after the summit.

When the 32 NATO members meet at their summit in Ankara in early July, they will face a paradox: the alliance’s deterrence and defence posture appears stronger and more comprehensive than at any point since the end of the Cold War. Yet, this military adaptation is unfolding against a backdrop of growing uncertainty about the future political foundations of transatlantic security. As European allies assume greater responsibility for collective defence, NATO is becoming more European militarily but without necessarily developing a corresponding capacity for political leadership.

At last year’s summit in The Hague, allied leaders agreed to a new defence spending target of five percent of GDP on defence and security by 2035. The decision, which the Trump administration had strongly pushed for, reflected more than concerns about military readiness. For many European governments, it was also an acknowledgement that maintaining American engagement in the future would require still more visible European contributions, despite the substantial financial and political costs involved.

In military terms, NATO’s adaptation since 2014 has been remarkable. Triggered initially by Russia’s annexation of Crimea and accelerated dramatically by the full-scale invasion of Ukraine in 2022, the alliance has undertaken its most significant transformation in decades. NATO has adopted regional defence plans, revised its force model, increased readiness requirements, strengthened its command structure, and expanded its forward presence both in geographic scope and in terms of capabilities. New and adapted vigilance activities, from the eastern flank to the High North have improved situational awareness and operational coordination. In addition, between 2014 and 2025, European allies doubled defence spending in real terms, expanded national procurement programmes, and more recently assumed a growing role within the military institutions of the alliance.

At the operational level, the direction of travel is therefore clear. NATO’s military adaptation has made the alliance significantly better prepared, more integrated, and better positioned to respond to a major crisis than only a few years ago. While important capability gaps remain and European forces continue to rely on critical American enablers in areas such as intelligence, logistics, aerial refuelling, and command-and-control, Europeans are assuming a larger share of the burden associated with deterrence and defence. Paradoxically, it is precisely the success of this military adaptation that brings deeper political questions into sharper focus.

For much of the past decade, debates about European security were dominated by concerns about defence spending and military capabilities. Today, these questions have not disappeared, but they are being complemented by another: what happens if the United States plays a less central political role within the alliance? To some extent, this is a new concern. Successive American administrations have encouraged Europeans to assume greater responsibility for their own security, while Washington’s focus has steadily shifted toward the Indo-Pacific. At the same time, American support for a larger European role has traditionally rested on the assumption that it would strengthen rather than fundamentally alter US leadership within NATO. Recent developments, however, suggest that Europeans will have to prepare for a future in which American leadership, and the predictability that has traditionally accompanied it, is either uncertain or missing entirely.

Several decisions taken over the past months have lent weight to this perception. In April, the US Army abruptly cancelled the scheduled rotational deployment of the 2nd Armored Brigade Combat Team (ABCT), 1st Cavalry Division, to Poland. As a heavy armoured formation with significant combat power, the brigade had become a regular component of the reinforced US military presence on NATO’s eastern flank since Russia’s annexation of Crimea in 2014. In parallel, the Pentagon terminated plans for a long-range strike battalion in Germany which, under the July 2024 bilateral agreement between Washington and Berlin, was expected to field Tomahawk cruise missiles, SM-6 ballistic missiles, and eventually the Dark Eagle hypersonic weapon system. Finally, in mid-May, the Department of Defense informed allies that it would reduce the US contribution to the NATO Force Model, meaning that fewer US capabilities would be directly available for the defence of the Alliance in times of crisis.

Individually, these decisions appear manageable from a military perspective. Their significance, however, lies in what they reveal about planning assumptions, force availability, and the future of America’s role within the alliance. For most of NATO’s history, the US did not merely provide the largest share of military power within the alliance, it also acted as its principal force integrator, political coordinator, and agenda setter. Washington has shaped force planning, provided political direction, and frequently brokered compromises among allies with different interests and threat perceptions. As long as this role remained largely uncontested, differences among European allies were easier to manage.

Today, Europeans face a more complex environment. American engagement may become less predictable, and US and European priorities may diverge more frequently, whether regarding Russia, the Middle East, or future procurement decisions. Under these conditions, Europeans are assuming greater responsibility not only for the defence of the continent, but also for maintaining political cohesion and providing direction within the alliance.

In response, European governments have not remained passive. The past years have seen the expansion of a network of bilateral, regional, and minilateral arrangements. Some focus primarily on military cooperation, force integration, and capability development, including the Joint Expeditionary Force, Nordic Defence Cooperation (NORDEFCO), and a growing number of bilateral initiatives. Others provide platforms for political and strategic consultation, such as the E3 and the Bucharest Nine. More recently, France has started discussions with selected allies on the future role of its nuclear deterrent and what Paris describes as “forward deterrence”. The fact that these discussions are unfolding through a series of bilateral conversations rather than a broader European framework illustrates both the growing strategic ambition of some European states and the absence of a commonly accepted mechanism for addressing such questions collectively.

As a result, while such initiatives demonstrate that mechanisms for military cooperation and political consultation do exist, none is designed to provide alliance-wide planning, coordination, and political direction. Nor is it entirely clear how these various efforts fit together within a broader framework capable of translating growing European responsibility into collective strategic action. A larger European role within NATO, however, requires a greater degree of convergence in how allies assess deterrence, escalation risks, and the use of military force. Without such convergence, the proliferation of military initiatives and consultation formats may ultimately reinforce fragmentation rather than coherence.

It would be unrealistic to expect the Ankara summit to resolve any of these fundamental political questions. Instead, one can expect that much of the discussion will focus on already adopted spending targets, force generation, and burden-sharing arrangements, and rightly so. NATO’s ongoing adaptation process and unilateral US decisions have created the foundations for a larger European role in transatlantic security. Whether Europeans can sustain that role politically remains uncertain. Thus, the value of this summit may ultimately lie in whether it helps Europeans begin addressing the political implications of a military transformation that is already underway.

The European Leadership Network itself as an institution holds no formal policy positions. The opinions articulated above represent the views of the authors rather than the European Leadership Network or its members. The ELN aims to encourage debates that will help develop Europe’s capacity to address the pressing foreign, defence, and security policy challenges of our time, to further its charitable purposes.

Image credit: Wikimedia Commons