Since the onset of the war in Ukraine, the geopolitical landscape in Europe has been irrevocably altered, prompting the president of France Emmanuel Macron to emphasize that France’s vital interests possess a “European dimension.” While this concept is not new—appearing in the president’s discourse in 2020—it piqued the curiosity of European allies who started wondering if France would offer them new security guarantees and how those would complement, or conflict, existing security guarantees from the United States.

In the context of Russia’s war of aggression in Ukraine, which looms under a nuclear shadow cast over Ukraine, European countries have rediscovered nuclear dynamics. The uncertainty surrounding the effects of the upcoming U.S. elections also encouraged Europeans to reinvest in strategic thinking and explore additional security guarantees.

France’s existing nuclear doctrine provides insight into how a “French offer” could complement U.S. extended deterrence, especially given the growing need for Europeans to take a more proactive role in their own security. For this idea to become fully operational, Paris would need to reassure Europeans that it intends to offer additional protection rather than replacing existing nuclear-sharing arrangements on the continent. Meanwhile, European countries could play a role in shaping expectations for this potential new contribution to their security.

The Confusion Around the 2020 French Offer

In 2020, in a speech that outlined France’s nuclear strategy for his mandate, President Macron underscored the “European dimension” of France’s vital interests. He invited European partners to engage in a strategic dialogue with France on “the role played by France’s nuclear deterrence in [their] collective security.” The timing of this speech, just weeks before the Covid-19 pandemic, likely hindered the initiative’s momentum and European countries largely ignored the offer. At the time, relations between European countries and France were relatively weak, with considerable distrust over Paris’s approach to Moscow. European allies also possibly anticipated that France would follow up with a more precise “menu” detailing what the “strategic dialogue” and “association with exercises of French deterrence forces,” as alluded to by Macron, could entail.

More recently, many political leaders and observers across Europe have sought to add substance to this presidential offer, often reflecting their own national preoccupation. For Germany, it revealed concerns regarding financial burden-sharing and leadership in defense policies amid the ongoing war in Ukraine. For Poland, it was about leveraging additional security guarantees—ideally in the shape of an eastern geographical extension of NATO’s nuclear mission—to counter the threat posed by Russia. The United Kingdom showed polite interest—the recent difficulties regarding its own deterrent could justify exploring new routes to bolster it in the long run—but also questioned the viability of a European initiative not endorsed by Washington.

These recent European reflections on France’s offer were prompted by concerns over U.S. reliability in the context of the upcoming U.S. presidential election and its possible impact on alliances. Nonetheless, the “French offer” should not be mistaken for a French willingness to replace the United States’ role in Europe. Considering alternatives to the U.S. extended deterrence would likely mean that the security context of Europe would have dramatically degraded and that the United States’ role as the main guarantor of its security would have significantly decreased. These two cumulative conditions, if they were to happen in the future, could trigger a new reflection on the role of French nuclear weapons in Europe. This, however, would go beyond the original intent behind the “European dimension” of the French nuclear deterrent.

Understanding the “European Dimension” in the Existing French Doctrine

The existing French nuclear doctrine provides clues on how a “European dimension” to France’s nuclear deterrent has added security insurance for Europe and could be further implemented in the future. To achieve this, several misunderstandings must be cleared up.

The European dimension of French deterrence should not be understood as a desire to establish an expanded European deterrence. The notion that French vital interests encompass a European component dates back to the 1970s, when French nuclear elites began to factor European integration into their nuclear calculus concluding that France’s vital interests “do not stop at France’s borders” (from the White Book of 1972). In 1994, former French president François Mitterrand urged Europe to “adopt clear notions of common vital interests.” In 2006, his successor Jacques Chirac embraced the previously established concept of “concerted deterrence” that could, when the time arises, complement the European Union’s Common Defense. In 2008, former French president Nicolas Sarkozy introduced the idea of “an open dialogue on the role of deterrence and its contribution to our common security.” After him, President François Hollande also alluded to this aspect of the French deterrent in his 2015 speech, rhetorically asking “Who could believe an aggression endangering the survival of Europe would have no consequences?” The common thread in these statements is that successive French presidents—who alone have the authority to determine the French nuclear doctrine—have linked French nuclear deterrent objectives to the consolidation of the European community, particularly but not exclusively in terms of defense at the European Union.

The principle of “strict sufficiency,” which governs the size and composition of the French nuclear arsenal, could be maintained and still provide the security insurance it provides today, even if the “French offer” gave way to more explicit security commitment towards more specific European allies. One of the main criticisms of the French “European dimension” is that the French arsenal, comprising fewer than 300 warheads, is too small to offer Europe the same level of security assurances as U.S. nuclear weapons forward deployed on the continent. It is highly unlikely that Paris ever intended to match U.S. capabilities as France does not seek nuclear parity. Nevertheless, France’s “theory of success,” given the limited size of its arsenal, constitutes a useful complement to NATO’s nuclear deterrent. The format of the French arsenal is predicated on the idea that nuclear weapons are defensive in nature and should not be employed to wage war. The arsenal, with a naval and an air-borne component, is designed to enable France to inflict “unacceptable damage” on potential adversaries in light of the stakes involved in threatening its vital interests. The current French doctrine also provides for a “warning shot,” a nonrenewable nuclear detonation that should suffice to reestablish the credibility of French deterrence. The “warning shot” is an existing option that could signal to a potential adversary that a line has been crossed regarding “European vital interests.”

The principle of “independence,” which is fundamental to the history and doctrine of French deterrence, suggests that any deepening of the “European dimension” would require developing new methods of consulting among Europeans and allies in general. This principle covers political as well as technical and operational aspects. It is one of the reasons why integration into NATO’s Nuclear Planning Group (NPG) has always been rejected by French political leaders and public opinion, and that France did not join the NPG when it reintegrated NATO’s military command structure in 2009. France remains the only NATO member outside of the NPG, while the two other nuclear weapon states of the Atlantic Alliance, the United States and the United Kingdom, are part of it. France has nonetheless engaged with allies on nuclear issues. In particular, since the onset of the war in Ukraine, France has contributed to policy discussions and initiatives on nuclear matters within NATO. It has also progressively and discreetly involved European partners in its annual nuclear exercise, Operation Poker, notably in red-teaming activities.

Preparing Future Conversations with France on Its “European Offer”

Looking ahead, a more explicit acknowledgment of security guarantees to European allies by France may not necessitate a change in the size of its arsenal or a complete doctrinal overhaul, but it would require some adjustments and some substantial discussion amongst allies and partners.

First, it would necessitate more substantial dialogue with willing European partners in order to define new or more specific “European” vital interests. This dialogue would likely be followed by a recognition of a more specific coverage of European interests in French declaratory policy, modeled on the UK-France Chequers declaration, which explicitly recognizes both nations’ mutual and intertwined security interests. All of this would need to be accomplished through thorough bilateral and ad hoc discussions with willing and able Europeans. European allies should also be reassured that France’s proposal offers additional protection rather than replacing existing nuclear-sharing arrangements on the continent. This reassurance could only be achieved through bilateral engagement between France and the future U.S. administration, clarifying U.S. commitments to Europe and French intentions to support European security.

Second, any new declaratory commitment should be supported by credible technical means, as France’s European partners and their potential adversaries perceive them. If France were to acknowledge a more specific protection for its European partners, it might require adjustments to its nuclear planning to signal more clearly when a “European vital interest” is at stake, thereby inflicting unacceptable damages on potential adversaries if necessary. This could be accomplished through changes in exercises (such as overflight of European allies’ territories) or, in the longer term, by associating European allies with signaling maneuvers or temporarily deploying French fighter-bombers outside France. Many more options could be contemplated, but there should be (at least) a bilateral agreement.

Ultimately, advancing the “European dimension” of the French deterrent might include rethinking the relationship between France’s nuclear decisionmaking and NATO’s NPG, which remains the reference point on nuclear matters among European allies. Discussions between France and other Europeans could establish a solid foundation for addressing concrete implications of the French “European dimension” for the existing framework for nuclear deterrence on the European continent. As NATO continues to assess its nuclear mission in the wake of the war in Ukraine, it would be valuable to consider how France could contribute more significantly to the alliance’s strategic thinking. Having discussions on the different ways to provide conventional support for nuclear operations, without delving into nuclear planning, could lead to mutually beneficial perspectives in the current context.

What’s Next?

Transforming the “European dimension” of French deterrence into a tangible contribution to the continent’s security will require careful navigation by France and its allies. However, out-of-the-box thinking may be essential to respond effectively to the rapidly changing security environment.

It will require substantive discussions to clarify France’s intentions. The intrinsic strategic ambiguity of the “European dimension” has often been misunderstood, and sometimes seen as destabilizing. Paris could be more specific about how its nuclear doctrine already contributes to Euro-Atlantic security. There should be greater visibility regarding the complementary nature of the French contribution, emphasizing that it is not a replacement for U.S. security guarantees in Europe.

Once objectives, concrete means, and governance structures are clarified—which will take time—the emergence of a genuine European strategic culture could pave the way for a steady contribution to the security of Europe.

Astrid Chevreuil is a visiting fellow with the Europe, Russia, and Eurasia Program at the Center for Strategic and International Studies in Washington, D.C.