How does France’s nuclear deterrent contribute to the defense of Europe?

A historical overview of the French nuclear deterrent

France’s first efforts to develop a nuclear weapon date back to the mid-1950s. Based on scientific research that had begun even before World War II under the leadership of Frédéric Joliot-Curie, France’s goal at the time was to acquire the industrial capability, particularly for the production of fissile material, to build its first weapon in the early 1960s. The main strategic rationale was that in order to survive in the post-World War II world, it was essential to possess nuclear weapons. This reasoning was fueled largely by Soviet nuclear blackmail and a lack of American backing to resist it, during the Franco-British operation in Suez in 1956.

Upon his return to power in 1958, General de Gaulle found a well-advanced nuclear program in place, enabling the first French nuclear test on February 13, 1960. He deliberately steered the program toward the creation of a fully sovereign and independent nuclear strike force, convinced that in this domain, decisions cannot be shared – especially with a more powerful ally that does not necessarily have the same interests. American hostility toward this policy of nuclear independence, coupled with NATO’s adoption of the “flexible response” doctrine – widely perceived in Paris as an elastic doctrine allowing the U.S. to avoid nuclear involvement in the defense of Europe – led to France’s withdrawal from NATO’s integrated military command in 1967. The reflections on nuclear doctrine conducted under the aegis of General Lucien Poirier, as set out in the 1972 White Paper on Defense, clearly stated that a country’s vital interests could be defined only by “reference solely to that country itself”.1 The perception that the French nuclear deterrent protected France – and France alone – thus became firmly established both in France and among its European allies. Nevertheless, the same 1972 White Paper emphasized that the limits of these vital interests must necessarily remain vague and that the logic of deterrence relies on a degree of uncertainty. Noting that France was not isolated and existed within a web of intertwined interests with its European neighbors, it thus pointed out that France’s nuclear deterrence strategy was a determining factor in European security. General de Gaulle had, in fact, clearly stated back in 19632 that nuclear weapons could, if necessary, play a part in protecting France’s allies. The contribution of France’s nuclear deterrent to the defense of Europe was recognized by its allies at the 1974 NATO summit in Ottawa. The final communiqué acknowledged that the two European states possessing nuclear forces were capable of playing a distinct deterrent role that contributed to the overall strengthening of Europe’s deterrent. It was primarily the role of London and Paris as a second decision-making center – complicating the adversary’s calculations – that this acknowledgement highlighted.

Nevertheless, the notion that the French deterrent served exclusively to defend France persisted throughout the Cold War, as evidenced by a famous exchange that took place in June 1987 during a meeting of G7 heads of state and government in Venice.3 Asked by Margaret Thatcher about the use of French nuclear weapons were Bonn to be invaded by the Soviets, François Mitterrand replied that such a scenario would mean that the deterrent had failed. This was a situation that must not be allowed to occur. And, moreover, the mission of protecting the Federal Republic of Germany and Western Europe was the responsibility of the North Atlantic Alliance, not that of France.

However, the post-Cold War era and the construction of a political Europe in the 1990s led French statesmen to attempt to integrate this European dimension into their national deterrent more effectively. It had certainly been present since the beginning but had never been properly developed. In 1995, French Prime Minister Alain Juppé proposed to Germany the concept of “concerted deterrence” between the two countries. This proposal did not meet with a favorable response at the time. The lack of interest in the French deterrent among European countries, starting with Germany, during a period of happy globalization and the United States’ continued commitment to NATO, would thus persist for some thirty years. The only country with which France made progress in this area during that period was the United Kingdom.

The Franco-British nuclear axis 

Political talks between the two European nuclear powers led to the creation of a Joint Nuclear Commission in 1992. The initial discussions within this framework focused on comparing the two deterrents in terms of concepts and doctrines, missile defense, and nonproliferation. These discussions revealed that the two countries’ nuclear doctrines were closely aligned. In late October 1995, British Prime Minister John Major and French President Jacques Chirac issued a statement (the so-called Chequers Declaration) in which they affirmed that they could not identify any situation in which the vital interests of one of the two powers might be threatened without those of the other power also being threatened. This declaration was systematically reiterated in the following years by the leaders of both nations, including after Brexit, until it was reinforced by the Northwood Declaration in 2025. This bilateral agreement clearly signaled a strong strategic alignment regarding the vital interests of both nations. Studies on the adoption of a joint air-launched nuclear missile, the ASLP4 were conducted, but without success. The British ultimately rejected this option, given the risks it could pose to their nuclear relations with their American ally.

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Jean-Louis Lozier is an Advisor to the Security Studies Center at the French Institute for International Relations (Ifri) and a naval officer who has served for 39 years in the French Navy. His career at sea has been mainly onboard submarines. Among others, he commanded two nuclear-powered ballistic missile submarines (SSBNs) (2004–2006). Promoted flag officer in 2012, he held during eight years high responsibility assignments, among them head of the nuclear forces directorate and inspector of nuclear weapons. As vice-admiral, his last assignments were “préfet maritime de l’Atlantique” and commander of operations in the Atlantic and Arctic areas.

• This article is available on the website of the journal Ethics and Armed Forces.