Research Group on 'Traditional Security Risks' FY2024-# 3
"Research Reports" are compiled by participants in research groups set up at The Japan Institute of International Affairs, and are designed to disseminate, in a timely fashion, the content of presentations made at research group meetings or analyses of current affairs. "Research Reports" represent their authors' views.
On February 21, future German chancellor Friedrich Merz issued a truly Zeitenwende-like statement in the midst of growing doubt over the Trump administration's commitment to NATO: "We need to have discussions with both the British and the French -- the two European nuclear powers -- about whether nuclear sharing, or at least nuclear security from the U.K. and France, could also apply to us."1
This apparent call for a debate on extended nuclear deterrence besides the United States has led French President Emmanuel Macron to reopen the debate on the European dimension of France's nuclear deterrence through a series of interviews. The momentum generated by these declarations has brought French nuclear deterrence to the forefront in an unprecedented manner, which calls for some clarification about its European dimension, as it remains a topic of debate, misunderstanding and controversy both in France and in Europe.
Continuity and changes in President Macron's recent remarks
President Macron said in an interview on February 28: "France has always acknowledged a European dimension to its vital interests, with some ambiguity. [...] If my colleagues want to move towards greater autonomy and deterrence capabilities, then we will have to open this deeply strategic discussion."2
On March 2, he added that allies willing to do so could be associated to the nuclear deterrence exercises carried out by the French forces, "contributing to the development of a genuine strategic culture between Europeans."3 This message reiterated a proposal made during his speech on defense and deterrence strategy in February 20204, following which Italy participated in a "Poker" French nuclear exercise in 2022.
Finally, on March 5, the President delivered an official television address to the French public, which is quite rare when it comes to defense and security issues: "Our nuclear deterrence protects us. It is comprehensive, sovereign, and French from A to Z. Ever since 1964, it has always explicitly played a part in the preservation of peace and security in Europe. In response to the historic call of the future German Chancellor, I have decided to open the strategic debate on the protection of our allies of the European continent by our deterrence. Whatever happens, the decision has always been and will remain in the hands of the President of the Republic, commander-in-chief of the armed forces."5
While the European dimension of France's vital interests, and thus its nuclear deterrence, has been acknowledged to varying degrees by all French presidents6, the main novelty here lies in the recurrence of official statements on the matter within such a short time frame, since traditional French thinking on nuclear deterrence can be summarized as "the less we talk about it, the better".
The vocabulary used by the President is also meaningful. He did not mention NATO or the EU but rather referred to the "European continent". This language reflects the evolution of Macron's thinking on French and European security since February 2022. He has come to realize that the pursuit of European "strategic autonomy" and security, which he has consistently advocated, must start with the Eastern European allies that he had initially neglected in his attempt to discuss a European security architecture with Russia.7
It can therefore be assumed that the geographic scope implied by this expression is intended to include the Baltic states and Poland in these discussions, as there has been an increasingly clear link between the development of the EU and the perception of French vital interests. As European solidarity grows stronger, it becomes more difficult to envision a situation where the vital interests of an EU country would be threatened without France's vital interests also being at stake. However, this expression remains ambiguous as there is no clear guarantee, and questions can be raised about whether it also intends, ultimately, to include Ukraine and Moldova, as they remain the primary targets of Russian aggression and threats on the European continent.
However, the current focus of the debate is not on nuclear-sharing or extended nuclear deterrence. French nuclear thinking since the 1960s has consistently questioned the credibility and effectiveness of such arrangements. France has no intention of sharing its nuclear weapons, let alone decision-making authority. As long as US nuclear weapons remain stationed in Europe under nuclear-sharing agreements, France will not present itself as an alternative. Rather, the objective of these statements is to foster deeper discussions about the role France's nuclear deterrent could play in Europe's security, as a form of complementary guarantee - a topic that remains fraught with misunderstandings and uncertainties among allies due to a lack of communication and dialogue.
Domestic and European challenges in the debate over the European dimension of France's nuclear deterrent
This debate must clearly address the two core dimensions of deterrence credibility: political credibility (declaratory policy and reassurances) and technical credibility (capabilities).
France's proposal to open the debate has been welcomed by several European countries, such as Poland and the Baltic states.8 In contrast to the relative indifference with which Macron's initial proposal to discuss these issues in 2020 was met, such reactions from staunch NATO supporters reveal the extent of the shock experienced by European allies, as it is becoming increasingly clear that a Trump administration would not risk nuclear conflict with Russia over Europe.
This is especially significant since these states feel more directly threatened by Russia than most other European countries. Reactions from Eastern Europe therefore highlight the most fundamental issue surrounding the expression "European dimension": geography.
The reality of the French nuclear doctrine is that some areas of Europe can already be regarded as tacitly covered by French deterrence. Although there is no formal equivalent of the Chequers Declaration9 with these countries, it is difficult to imagine a situation in which the vital interests of Germany, Belgium or the Netherlands would be threatened without also putting France's vital interests at risk. In this regard, geography matters, which is precisely why the positive response from Eastern European capitals calls for greater French clarity in the forthcoming debate.
Indeed, one of the core principles of French nuclear deterrence is its ambiguity: the definition of France's vital interests and the extent to which they might be threatened are solely determined by the President. While such opacity is intended to strengthen deterrence by complicating adversary calculations, it would inevitably elicit reluctance and unease from European allies. More concrete discussions among allies are therefore required to clarify the meaning of the European dimension of France's vital interests and the foundations of its nuclear doctrine.
Moreover, although France's proposal to debate its nuclear deterrent has been positively received, it still lacks an appropriate forum for discussion. France has never been part of NATO's Nuclear Planning Group (NPG), which is the traditional platform to discuss nuclear deterrence-related issues within the alliance. Some prominent French researchers have suggested that France join the NPG as an observer.10 Such a move would indeed lend more credibility to France's willingness to discuss its deterrent while maintaining distance from NATO's nuclear planning. It would also help avoid the impression that France is seeking to build an alternative framework to exclude or replace the United States. However, if France truly views Russia's invasion of Ukraine as an existential threat, it must find ways to involve non-NATO countries such as Ukraine and Moldova in the debate about its nuclear deterrence.
In terms of technical credibility, there is ongoing debate among French specialists about whether France's current nuclear capabilities would be sufficient to provide extended deterrence to the European continent against Russia. France's nuclear deterrence is based on a minimal nuclear arsenal sufficient to inflict "unacceptable damage" on an adversary. Unlike the US model, it does not require as many nuclear warheads, partly because geography could lend greater credibility to its role in protecting the European continent. Nevertheless, the ability to cause "unacceptable damage" in defense of France is not the same as the ability to do so in defense of the European continent. In such a scenario, questions would arise about whether the current French arsenal is both quantitatively and qualitatively sufficient to reassure allies and deter adversaries.
Moreover, it is highly unlikely that France could successfully "Europeanize" its nuclear capabilities in the near future: the air-launched ASMPA-R nuclear missile would need to be adapted for aircraft other than the Rafale; France would likely have to move beyond its doctrine of "strict sufficiency"11 to develop more warheads; the establishment of dedicated military bases in allied countries would entail extremely high costs...
However, this crucial discussion is not at the core of the issue at hand. The ongoing debate is not about technical developments but rather political dialogue among allies to determine how France can contribute more to European security. For now, the necessary discussion on European capabilities is not so much nuclear as conventional.
Although Russia's full-scale invasion of Ukraine has been ongoing for over three years, many gaps remain, particularly in terms of long-range precision strike capabilities. Initiatives such as the European Long Range Strike Approach (ELSA) must be strengthened as discussions on the European dimension of France's nuclear deterrence intensify. The role of capabilities such as the French SCALP, British Storm Shadow, and German Taurus must be defined collectively to strengthen conventional deterrence, as nuclear weapons alone cannot deter every threat or hostile action. To deter aggression below the level of nuclear conflict and retain more options on the escalation ladder, the development of robust European conventional capabilities is a higher priority than the more distant prospect of French extended nuclear deterrence.
Finally, France's domestic political situation raises uncertainty about the long-term durability of its openness to discuss the European dimension of its nuclear deterrence. From a financial standpoint, France's dire budgetary situation casts a constant shadow over the feasibility of bold and far-reaching policies, even though the budget allocated to the armed forces remains relatively untouched and is likely to increase.
From a political perspective, the 2027 presidential election will pose significant challenges for this debate. As President Macron will not be able to run for another term, the two dominant contenders are expected to be far-right leader Marine Le Pen and far-left leader Jean-Luc Mélenchon. Both vehemently oppose the idea of greater European defense and have consistently argued that nuclear deterrence cannot be shared, while also expressing frequent hostility toward NATO. Additionally, Le Pen and her party are known for their strong ideological ties and proximity to the Kremlin, while Mélenchon has, on several occasions, aligned with Russia's narrative that NATO's expansion was one of the causes of the war. The willingness and the determination of the current French presidency to engage in this dialogue with European allies do not guarantee that this momentum will be sustained by future leadership. The long-term viability of the French proposal therefore remains highly uncertain.
In conclusion, France's willingness to discuss its nuclear deterrence with European allies and partners is a clear signal of the current leadership's understanding of the evolution of European security, in the context of Russia's aggression of Ukraine and Europe and doubts over the Trump administration's commitment to NATO. Whether it marks a turning point in the history of European security will depend on the concrete political and technical initiatives that follow. Given the unpredictability of the French political landscape and the opposition of France's major political forces to this debate, allies must seize the opportunity to engage in these discussions swiftly, while prioritizing steady and comprehensive development of conventional capabilities to fill the remaining deterrence gaps.