Every few years, the idea of a European nuclear deterrent resurfaces in European expert and policy circles. This resurgence has been particularly notable in light of the potential return of Donald Trump to the White House. While some once again float trial balloons about a Eurodeterrent, most experts doubt it will lead to real action. They argue that a European nuclear deterrent is currently neither feasible nor desirable. However, underlying these discussions are real concerns about European security. It is reasonable and prudent for Europeans to consider hedging against an unreliable security patron in Washington and a reckless and aggressive leader in Moscow. Any hedging strategy, and related capabilities, should therefore be anchored in an analysis that considers these factors in conjunction. For now, without a clear understanding of the nature of the threat posed by Russia to regional security, a European nuclear arsenal is essentially a capability without a concept. Rather than fixating on replacing the US nuclear umbrella, the priority should be to define Europe’s “Russia problem” and consider various approaches to best address it. Proposals that focus on capability divorced from concept are unlikely to make anyone better off. The Euro-deterrent debate: The perpetual specter of US abandonment The discussion of a European nuclear weapon is far from new, and often resurfaces during periods marked by doubts about the US resolve to use nuclear weapons in defense of its European allies. Importantly, there is no specific agreement obligating the United States to use nuclear weapons in any given situation. Article 5 of the Washington Treaty commits the United States to “take the actions it deems necessary” to assist a NATO ally when under attack, but by no means include any stipulations about the scope and nature of this aid. Whether or not any aid package may include nuclear weapons is an open question. U.S. nuclear policy, for its part, operates under a principle of “calculated ambiguity”, meaning that it does not specify which conditions would merit nuclear use. For over more than seven decades, it has been a daunting challenge for Washington to try and convince its European allies that its security commitment includes the credible promise that it may use a nuclear weapon in response to at least some threats. After all, the decision to use a nuclear weapon on behalf of others, particularly in the face of potential nuclear retaliation, is not a light one. Donald Trump’s repeated dismissive remarks about NATO have eroded the trust among some European allies in this commitment, especially amid escalating tensions with Russia. If they cannot rely on the US, so the argument goes, their proposed solution is to pursue greater autonomy through the development of a nuclear weapon under European control instead. Proposals for European nuclear alternatives vary, ranging from the development of an EU nuclear weapon to new nuclear weapons states in Europe or an expanded role for existing nuclear powers France and the UK. Yet, each of these alternatives faces important obstacles. Some European critics oppose the practice of nuclear deterrence altogether, while others express concerns about the impact of a European nuclear weapon on global nuclear non-proliferation efforts. Additionally, there are important political and practical challenges regarding control over a European arsenal. In short, despite renewed discussions, the prospect for a European nuclear arsenal continue to seem exceedingly dim. The underlying issue: Europe’s Russia problem One could easily dismiss the entire conversation about a European nuclear deterrent as misguided and impractical. However, underlying these calls are valid fears of US abandonment. These fears, in turn, serve as proxies for a more fundamental question: How should Europe cope with an increasingly aggressive and reckless Russia? Indeed, since the Russian annexation of Crimea in 2014, followed by a full-scale invasion of Ukraine in 2022, concerns about a resurgent Russia continue to grow in many European capitals. Besides the Ukraine war, there are clear indications of Russian efforts to disrupt the democratic process and institutions across NATO members. The Kremlin has also used energy resources and migration as tactics to try exert influence over European NATO allies. While observers have gathered important information about Russia’s military capabilities and the different ways in conducts warfare, much uncertainty persists about how these align with the Kremlin’s overall strategic goals. Despite widespread speculation about the Kremlin’s alleged plans for territorial grabs in Estonia, Latvia or Norway, the extent to which many of these predictions reflect actual Russian thinking remains an open question. Further complicating matters is the persistent uncertainty about Russian losses in its ongoing combat operations in Ukraine, and when these will end. The growing calls to strengthen deterrence compelled one renowned NATO watcher to ask a poignant question to which a clear answer is yet to be formulated: “What, exactly, is Russia preparing for?” The assessment of the European security environment to which calls for a European nuclear deterrent respond is hard to contest. Given the uncertainties surrounding the reliability of the United States and the Kremlin’s reckless behavior, it is prudent for Europeans to contemplate a hedging strategy. However, any such strategy must be founded on an analysis that takes into account both factors. Currently, without a clear understanding of the precise security risk posed to the region by Russia, the idea of establishing a nuclear arsenal lacks a sound strategic basis. It is a capability that is supposed to convince Russia from aggression in some form because of some unidentified wager. The lack of specificity that permeates this statement essentially undermines its validity as sound strategy. The path forward: Linking concept and capability Once Europeans get some degree of agreement and clarity on the type of Russian aggression to deter, the next step is to carefully consider the most effective means of addressing it. Here, policymakers should not fall into the trap of considering the option of a European nuclear weapon in isolation or assuming that nuclear deterrence somehow equals security. On the one hand, many scholars contend that nuclear weapons offer none or very little deterrence against activities at lower levels of conflict, such as cyber-attacks or disinformation campaigns. On the other hand, the proliferation of advanced non-nuclear weapons capable of reaching targets at the strategic level of raises important questions about deterrence strategy and nuclear risk overall. Ultimately, deterrence hinges on the ability to inflict harm on an adversary and increase the cost of aggression beyond its potential gains. While nuclear weapons are by many deemed effective in this regard, they are not necessarily the sole means capable of achieving such outcomes. Conventional precision-strike capabilities but also cyber and information weapons can today all potentially hold an adversary’s sources of national power at risk, and thus take on roles traditionally assigned to nuclear weapons. This reality ought to prompt Europeans to start by considering non-nuclear alternatives, weighing their associated benefits and risks, which may be equally or even more suitable for addressing the issue at hand. To be sure, strategies are always based on imperfect information about adversaries and must account for multiple scenarios. Instead of solely focusing on replacing the US nuclear umbrella, the primary task for Europeans is to define their Russia problem and adopt an open mind regarding how best to address it. The relationship between capability and concept is not obvious; it ought to be the topic of informed discussion and debate. Conclusion While the concept of a European nuclear deterrent is by most deemed ill-advised, it also stems from a deeper unease: How to navigate a world where Russia appears increasingly aggressive and the United States more unpredictable. Rather than hastily pursuing nuclear alternatives, European leaders must define their Russia problem first. If European leaders genuinely believe that Europe’s security environment has fundamentally changed since February 2022, then they must engage with the core issues in thinking of how to act in response. This requires a clear and explicit alignment between capability and concept which is currently lacking in the case for the Eurodeterrent.