From Asset to Liability: Europe’s Security Dependence on America

For decades, European governments accepted structural subordination within NATO in exchange for two assumptions: overwhelming US military power and the political reliability of a stable liberal democratic partner. That bargain is quickly eroding. Alliances built on hierarchical authority are sustainable only when the leading power is predictable and its commitments credible.[i] Today, both of those conditions are not satisfied. The United States is marked by sustained democratic backsliding and executive volatility,[ii] its governing foreign policy doctrine increasingly frames alliances in transactional and nationalist terms,[iii] and its leadership shows a growing willingness to employ large-scale coercive force in pursuit of unilateral strategic objectives, as illustrated by the recent military campaign against Iran. Under these conditions, structural security dependence becomes exposure rather than insurance.

The postwar transatlantic settlement was neither sentimental nor accidental. It was a rational exchange under conditions of asymmetric power and acute Soviet threat. Europe traded strategic autonomy for security guarantees – above all the American nuclear umbrella and escalation control – within a hierarchical alliance structure ultimately anchored in Washington.[iv] This subordination was politically sustainable because US power was embedded in a stable liberal constitutional order committed to rule-of-law governance, multilateral constraint, and institutional predictability.[v] In other words, the alliance was not merely military – it was normative. Regime similarity reinforced trust, reduced fears of abandonment, and underwrote deterrence credibility.[vi] That constitutional alignment also ultimately created the conditions for Europe’s own self-understanding as a civilian and normative power. Strategic dependence was tolerable because it rested on shared liberal foundations. It functioned as a stabilizing adaptation to power asymmetry within a constitutional order perceived as reliable.

What Has Changed: Volatility and Divergence

Democratic erosion in the United States is not merely a domestic development as it is paired with a serious redefinition of America’s role in the world that alters the risk structure of the transatlantic alliance. Hierarchical security arrangements depend on the predictability of the leading power’s commitments. Long-term alliance guarantees become structurally uncertain when executive authority becomes personalized, institutional constraints weaken, and foreign policy becomes electorally contingent. The American nuclear umbrella remains formidable in capability. However, what has become less certain is the stability, strategic orientation, and the very nature of the political decision-making process that governs its use.

Deterrence credibility depends as much on constitutional reliability as on military strength.[vii] For Europe, reliance on a guarantor whose commitments are increasingly mediated by domestic polarization and ideological contestation introduces strategic exposure where once there was strategic clarity.

Volatility, however, is only part of the problem. The governing foreign policy doctrine emerging in Washington reflects a deeper shift in strategic orientation. The new National Security Strategy of the United States,[viii] as well as recent statements by high-ranking American officials at the Munich Security Conference illustrate the pattern. Alliances are being framed in explicitly transactional terms, emphasizing burden redistribution over shared strategic purpose, and questioning the value of multilateral constraint.[ix] They are presented less as communities of shared liberal order and more as instruments of national advantage. At the same time, highly influential elements within the current US political leadership – most notably in the White House itself – have moved beyond transactional bargaining toward open political hostility toward the European integration project itself. This worldview prioritizes strategic flexibility, sovereignty over institutional binding, and great-power bargaining unconstrained by alliance consensus. For Europe – whose security architecture and political identity are built on multilateralism and legal constraint – such an orientation introduces structural divergence. Dependence becomes riskier when the guarantor’s strategic doctrine no longer consistently aligns with one’s own foundational interests or the very essence of one’s being. Simply put, continuing security subordination to the United States could hollow out the European project of its core meaning and internal logic.

Strategic Exposure in Practice

Recent escalation in the Middle East illustrates how structural dependence translates into exposure. The joint US-Israel strikes on Iran were not the product of European strategic design, nor were European governments participants in the decision-making process.[x] Yet the consequences reverberate directly through Europe’s security environment. As a geographically proximate actor with deep economic and diplomatic ties to the region, Europe faces heightened vulnerability to energy disruption, market instability, and potential secondary security spillovers. More fundamentally, renewed large-scale conflict in the Middle East risks diverting strategic attention and military resources away from the theatre that matters most to European security: Ukraine. For Europe, whose primary existential challenge remains Russian aggression, such strategic diffusion is decidedly negative. Dependence on an external guarantor means that decisions taken elsewhere can reshape Europe’s risk environment – and dilute focus on its core security priorities – without corresponding European authority over those choices. Exposure, in this sense, is structural rather than episodic.

Beyond Palliative Solutions

Recent adjustments within NATO – including greater European operational leadership and renewed commitments to defence spending – suggest some form of adaptation is taking place. Yet these changes leave the underlying hierarchy intact. Operational responsibility is not equivalent to strategic authority. Ultimate escalation control, including nuclear deterrence, remains external to Europe. The American nuclear umbrella continues to anchor NATO’s deterrence posture, while European governments possess limited influence over the decision structures governing its potential use.

It is therefore unsurprising that the nuclear dimension of European security has re-entered political debate. French President Emmanuel Macron recently proposed expanding the European role of France’s nuclear deterrent, including joint exercises and the possible deployment of nuclear-capable aircraft in allied countries.[xi] This initiative, however, does not address the core problem. NATO adaptation may redistribute responsibilities and French expansion of its national nuclear umbrella may offer short-term comfort to some of its partners, but they do not alter the fundamental asymmetry between those who bear the consequences of escalation and those who control the means of deterrence.

Moreover, the credibility of such an arrangement would itself depend on the stability of French domestic politics. Nuclear guarantees ultimately rest not only on capabilities but on political reliability across electoral cycles. In France, where the future direction of foreign and European policy is the subject of intense domestic contestation – including scenarios in which power could shift to nationalist leadership openly sceptical of European integration – the long-term predictability of such guarantees cannot simply be assumed.

Europe’s security dependence on the United States was once a rational response to asymmetric power within a stable liberal constitutional order that governed the transatlantic alliance. That context is changing. Volatility in American politics, divergence in strategic doctrine, and growing exposure to decisions taken outside Europe’s control are steadily altering the risk calculus of dependence. None of the responses currently under discussion fundamentally resolve this dilemma.

Greater defence spending, expanded European roles within NATO, and initiatives such as France’s proposal to broaden the role of its nuclear deterrent may mitigate immediate vulnerabilities, but they remain transitional measures. They adjust the existing architecture without altering its underlying asymmetry. The strategic question facing Europe is therefore more fundamental. Managing dependence is no longer sufficient. What is required is a step change in Europe’s own security integration – one that matches its economic and political weight with commensurate strategic authority. Durable security is only possible when the means of collective defence and deterrence are also collectively owned and controlled. For Europe, this implies moving beyond managed dependence toward an integrated security community in which nuclear, conventional and industrial capabilities are planned, financed, and governed at the European level, not merely coordinated among nation‑states.

Photo credit: NATO Headquarters, Brussels Belgium, Copyright NATO.

[i] David A. Lake, Hierarchy in International Relations (Cornell University Press, 2009).

[ii] Marina Nord, David Altman, Fabio Angiolillo, Tiago Fernandes, Ana Good God, and Staffan I. Lindberg, Democracy Report 2025: 25 Years of Autocratization – Democracy Trumped? (University of Gothenburg: V-Dem Institute, 2025).

[iii] J. D. Vance, “Speech at the Munich Security Conference,” Munich, February 14, 2025, transcript.

[iv] Lawrence S. Kaplan, NATO and the United States: The Enduring Alliance (Twayne Publishers, 1994).

[v] Bruce Russett and John Oneal, Triangulating Peace: Democracy, Interdependence, and International Organizations (W. W. Norton, 2001).

[vi] Glenn H. Snyder, “The Security Dilemma in Alliance Politics,” World Politics 36, no. 4 (July 1984): 461-495.

[vii] James D. Fearon, “Signaling Foreign Policy Interests: Tying Hands versus Sinking Costs,” Journal of Conflict Resolution 41, no. 1 (1997): 68–90.

[viii] The White House, National Security Strategy of the United States of America (The White House, November 2025).

[ix] Vance, “Speech at the Munich Security Conference.” Much has been made of the supposed difference in approach by the Secretary of State Marco Rubio in his speech at Munich Security Conference a year after Vance, but that difference was mainly in style, not substance. Marco Rubio, “Secretary of State Marco Rubio at the Munich Security Conference,” Munich Security Conference, Munich, February 14, 2026, US Department of State transcript.

[x] Reuters, “Global Reaction to Israeli, U.S. Attacks on Iran,” Reuters, February 28, 2026;Philippe Ricard, “France, Germany and UK’s Balancing Act in Response to US-Israeli Offensive against Iran,” Le Monde, February 28, 2026.

[xi] Henry Foy, “France Offers to Deploy Nuclear Deterrent across Europe for First Time,” Financial Times, March 2, 2026.