In recent weeks, a concept once confined to academic defense seminars has entered mainstream European politics: a "European nuclear umbrella." Both German Chancellor Friedrich Merz and French President Emmanuel Macron mentioned the idea during their speeches at the Munich Security Conference on Feb. 13, while officials from countries including Poland, Estonia, Latvia, Lithuania and Belgium have also recently expressed support for it. The term "nuclear umbrella" sounds dramatic — almost Cold War in tone — but the idea itself is less about building new weapons than about redefining who guarantees Europe's security in an era of strategic uncertainty. The discussion is primarily driven by doubt about whether the transatlantic security model that has protected Europe for nearly eight decades will function in the same way in the decades ahead.
For most Europeans born after 1945, nuclear deterrence has been an invisible background condition rather than a conscious political choice, as the continent lived under the American strategic guarantee, formalized through NATO's collective defense principle. The arrangement was simple: Washington extended its nuclear protection to allied states, making any attack on Europe equivalent to an attack on the United States itself. Several European countries hosted American nuclear weapons under so-called "nuclear sharing," while the United States maintained thousands of deployed warheads and a full strategic triad of intercontinental missiles, submarines and bombers. European countries did not need their own nuclear weapons; credibility flowed from American power and the political certainty that the United States was permanently committed to European stability.
What has changed is both geopolitics and psychology. Russia's ongoing (and likely long-term) confrontation with the West, the United States' shifting strategic focus toward Asia, the growing unpredictability of American domestic politics, lingering questions about the White House's commitment to NATO's collective defense and recent threats by the Trump administration against the territorial integrity of its allies have combined to produce new interrogants in European capitals: Can the American guarantee be trusted? And what if it becomes conditional — not withdrawn overnight, but diluted, delayed or politically contested at a moment of crisis? Nuclear deterrence depends less on capability than on belief, and once belief weakens, so does deterrence.
A Shared European Nuclear Guarantee?
The ongoing European nuclear debate does not start from zero. Two European countries already possess nuclear weapons — just not collectively controlled ones. France maintains roughly 290 nuclear warheads and a sea-air deterrent centered on four ballistic-missile submarines and air-launched cruise missiles. The United Kingdom maintains about 225 warheads carried exclusively by submarine-launched ballistic missiles on patrol submarines. Together, they represent the world's third-largest nuclear arsenal after the United States and Russia — not numerically comparable to Washington's roughly 5,000 warheads, but more than sufficient to destroy any aggressor's state infrastructure many times over. The question now under discussion is whether those national deterrents could function, politically and psychologically, as a shared European guarantee alongside the American one. This is a crucial distinction. Advocates are not proposing a single EU bomb, nor a replacement of NATO. Rather, they envision a European pillar within the existing alliance — a layer of deterrence that would make Europe less dependent on U.S. decisions without forcing a break from the transatlantic relationship. In essence, Europe would partially insure itself against potential changes in American views on transatlantic security pacts.
France plays a unique role in this discussion because its nuclear doctrine was always deliberately ambiguous. Unlike the American guarantee, which was explicitly treaty-based, the French deterrent historically protected "vital interests," a phrase intentionally undefined so that it could expand if necessary. French leaders have long hinted that those interests could include the security of Europe as a whole. The concept is therefore not new; what is new is the willingness of other countries, particularly Germany and Nordic and Eastern European states, to explore it seriously.
The United Kingdom adds another dimension to this discussion. British nuclear forces have been embedded in NATO strategy since their creation. They are designed less as a purely national shield and more as a reinforcement of collective deterrence. For many European states, especially those geographically closer to Russia, this matters enormously. A deterrent shared by two nuclear powers appears more credible than one extended by a single country, because it signals cooperation rather than unilateral protection. Technically, it also improves survivability: at any given moment, at least one British and one French submarine are typically on patrol, meaning retaliation could occur even after a devastating first strike. However, the United Kingdom's inclusion carries a technical caveat: unlike France's entirely sovereign arsenal, the British Trident system relies on shared American infrastructure and logistical assistance, meaning London might remain tethered to Washington's strategic whims, even if the rest of Europe seeks autonomy.
While Germany does not have any nuclear weapons, it is another key country in the equation because its participation would transform a bilateral Anglo-French capability into a continental commitment. Post-war German identity embedded military restraint and multilateral legitimacy. Domestic law and international treaties bar Germany from having nuclear weapons, and public support for acquiring them is low. However, domestic support for protection under allied deterrence is high. Germany's involvement signals collective responsibility rather than national ambition. During the Cold War, U.S. nuclear credibility in Europe depended heavily on West Germany's integration into NATO command structures; similarly, a European nuclear pillar would gain legitimacy if Germany visibly shared decision-making. Nevertheless, German participation would create a paradox for the country. If Berlin demands a veto over the use of European nuclear weapons, it risks paralyzing the deterrent during the critical minutes of a crisis; if it yields all authority to Paris or London, the guarantee may be as uncertain as the one currently provided by Washington.
The Credibility Question
The greatest obstacle to Europe's nuclear deterrence ambitions is credibility. Would Paris or London risk nuclear devastation to defend another European state? During the Cold War, critics asked whether the United States would trade New York for Berlin. Today, the question becomes whether Europe would risk one of its capitals for Warsaw or Tallinn. The success of deterrence depends on convincing adversaries (and allies) that the answer is yes — even if citizens themselves remain uncertain. While the European Union has remained relatively united on issues such as support for Ukraine's war efforts, the bloc still faces a credibility problem due to its consensus-driven policymaking and the often conflicting national interests and political priorities of its states. Building credibility will be Europe's main challenge if it wants to have a shared nuclear deterrent.
Command and control adds a similar challenge. Nuclear weapons require rapid centralized decisions, yet European political systems rely on consensus. A multinational, unanimity-based launch authority risks paralysis; a purely national authority risks mistrust. Any workable solution will likely resemble NATO's arrangements: consultation in peacetime, national decision in extremis, but embedded within a jointly planned strategy.
Public opinion compounds these difficulties. In many European countries, nuclear weapons are associated more with risk rather than with stability. During his speech at the Munich Security Conference, Spanish Prime Minister Pedro Sanchez warned against a European nuclear arms race and highlighted the financial burden of keeping a nuclear arsenal at a time when the continent should focus on climate change and the fight against poverty. Even German Defense Minister Boris Pistorius recently warned that European nations should be careful not to undermine the existing American-led NATO umbrella. These comments explain why even the governments most supportive of a European nuclear umbrella are moving cautiously, emphasizing dialogue, consultation and responsibility rather than announcing dramatic policy shifts.
Domestic politics will also shape Europe's nuclear credibility in decisive ways. A European nuclear umbrella will depend on the willingness of multiple states to act collectively under high-pressure conditions. Sovereignist, far-right or far-left governments, which emphasize national control and often resist continental integration, could oppose plans to develop a pan-European nuclear umbrella or, if one already exists by the time they take over, veto the use of nuclear forces in a crisis. Hesitation or political fragmentation among the members of the European nuclear umbrella could weaken signaling, reduce public legitimacy and slow the development of joint infrastructure. In short, Europe's deterrent is only as credible as the political cohesion behind it — and cohesion is far from guaranteed.
The final challenge is technical, because a truly autonomous European nuclear deterrent would require large, multi-decade investments that the continent may struggle to make. Currently, Europe relies almost entirely on American satellite constellations and early-warning networks to detect missile launches in real-time. Without developing sovereign space-based assets (a project that would cost billions and take years to deploy), any European nuclear umbrella would be effectively blind, incapable of responding to a threat without the very American data it seeks to hedge against. At a time when the continent is dealing with slow economic growth, aging populations and large debt burdens, investing a significant amount of money in nuclear deterrence will be a tough political sell in many European countries. This is especially true if non-nuclear members of the alliance are asked to use taxpayer money to fund the expansion and upkeep of the nuclear arsenals belonging to the nuclear member states.
The Road Ahead
Even the proponents of a European nuclear umbrella acknowledge that the continent cannot replicate the full American protection, at least for the time being. The United States maintains far larger forces, global surveillance systems and integrated missile warning networks. A European deterrence system would supplement rather than replace American guarantees, aiming for resilience amid transatlantic political turbulence. This explains why the ongoing discussion is evolutionary rather than revolutionary. However, this approach may soon collide with a harsher reality: Europe may not have the luxury of choice for much longer. If the American guarantee were to erode rapidly, the question of whether a European deterrent could fully replicate U.S. scale would become secondary to the urgent need for any credible alternative at all. Current efforts thus represent a dual-track race: prolonging reliance on the U.S. umbrella for as long as possible while buying the time needed to build the industrial base, technical capabilities and political cohesion for a potential European successor.
Against this backdrop, the debate about a European nuclear umbrella is likely to unfold gradually. In the first phase, already underway, European states are likely to deepen consultation without making any drastic moves. France and the United Kingdom will coordinate doctrine more openly, while Germany and others participate in strategic planning discussions. The change will be largely political: shared language, exercises and signaling that European security is a collective responsibility. The goal will be to send a message to the United States, Russia and others that Europe is having a conversation about the topic, while also introducing the issue in the national public debate without making any potentially unpopular decisions yet.
In a second phase, likely toward the late 2020s or early 2030s, the arrangement could become formalized. A European deterrence doctrine would emerge, linked to NATO structures but financed and politically endorsed by European governments. Non-nuclear states would contribute funding and infrastructure, strengthening the perception that the deterrent protects all members rather than merely extending national policy. The third phase remains uncertain and distant. Only if transatlantic relations deteriorate severely would Europe attempt a fully autonomous nuclear command independent of the United States. Such a step would require treaty changes if it's done within the European Union (multilateral, non-EU agreements are also possible), along with integrated command structures and a profound shift in public opinion — developments conceivable over several years but improbable anytime soon.
The likely outcome, therefore, is neither a European nuclear bomb nor the collapse of NATO. Instead, Europe will slowly start to carry part of its own strategic burden. The American umbrella will remain overhead, but beneath it a secondary canopy will start to form — European in responsibility, Franco-British in capability, and multinational in political meaning. In practical terms, the debate is not about Europe becoming a nuclear superpower but about ending a structural vulnerability in its security architecture as it advances toward greater strategic and defense autonomy from Washington. For decades, deterrence in Europe was politically external — guaranteed from across the Atlantic and therefore assumed rather than owned. A European nuclear pillar would not immediately replace the United States, but it would reduce the risk that a single political decision elsewhere could determine the continent's fate. If it emerges, it will do so quietly: procedures before proclamations and coordination before doctrine. The real shift would not be measured in additional warheads, but in responsibility — a Europe still anchored in NATO, yet no longer entirely dependent on choices made on the other side of the Atlantic.
