Emmanuel Macron has proposed opening a dialogue with other European countries on France's nuclear deterrent, raising questions about what a French nuclear umbrella over Europe might entail – although the Élysée has stressed that France is not seeking to deploy nuclear weapons outside the country, or to revise the nuclear doctrine.
"Never has the risk of war on the European continent, in the European Union, been so high, because for almost 15 years the threat has been getting closer and closer to us," declared French foreign minister Jean-Noël Barrot on Monday.
Caught off guard by an American president seemingly ready to review his historic alliances, Europe is being forced into revising its defence model and counting its troops.
France is the only country in the European Union with nuclear weapons, but now the French president says he is ready to open discussions on a potential European nuclear deterrent.
However, this does not imply any sharing of nuclear weapons, explained Elie Tenenbaum, research director at the French Institute of International Relations (IFRI) think tank.
"The deployment of French nuclear weapons abroad is not currently an option. And in the French concept of [nuclear] doctrine, the weapons are not shared and deterrence is not shared – indeed in any concept of doctrine, since the Americans do not share theirs either. Emmanuel Macron has said ‘it doesn't change our doctrine’," Tenenbaum told RFI.
What is changing, however, is how France views its strategic interests in relation to Europe.
"For the moment, we are not talking about a change of doctrine, we are talking about strengthening this European dimension that [Macron] mentioned in his February 2020 speech at the École Militaire," said Tenenbaum.
This European dimension involves France's vital interests – interests that could trigger the nuclear deterrent if threatened by an aggressor state.
A German change of heart?
Germany, which until now has relied exclusively on NATO and Washington for its security guarantees, has never asked for the cover of the French nuclear umbrella.
The country's entire political class has formally ruled out having to contribute to the funding of its neighbour's nuclear deterrent. But, according to Tenebaum, things are changing and the future German chancellor, Friedrich Merz, seems to be taking a different view.
"Ever since Donald Trump's ranting during his campaign, including about the fact that he might refuse to defend or honour his security commitments to NATO allies, there has been discussion in Germany about possible alternatives to a US nuclear security guarantee that could be undermined," Tenenbaum said.
This debate has been ongoing in German media for about a year, according to the expert.
With growing concerns about American reliability, Germany is looking at alternative security guarantees. The European options – France and the UK – have different capabilities than the US.
"But it's an arsenal dedicated to defending more limited interests than the American model. We have systems that were not designed from the outset to deter a wide range of interests," Tenenbaum said.
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These converging interests could lead to new forms of cooperation.
"Berlin is looking for alternatives and there is a French desire – including for political reasons – to emphasise the European dimension of its own deterrent. So these two interests are finally coming together and will hopefully lead to discussions.
But he cautioned that any collaboration would be modest in scope.
"We are talking about the participation of Europeans in French nuclear exercises. This has already happened with Italian participation in the French Air Force's Poker [nuclear air raid simulation] exercise.
European industrial projects
A joint industrial project for nuclear deterrence remains a distant prospect, according to Tenenbaum. The immediate focus is on strategic cooperation.
"We are talking about a strategic nuclear culture, about better integration of the nuclear factor into defence planning. When we draw up defence plans, at what point do we consider the link with the dialogue on deterrence?
This discussion is especially timely as NATO is currently developing its defence plans. On the technological front, there are opportunities for European collaboration.
"France's nuclear deterrent is based on its mastery of a number of technologies... So there are a number of technological building blocks on which we can work together," Tenenbaum said.
He cites the Ariane Group as an example – a European aerospace company working on both space access and ballistic technology, which are closely linked.
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"We need to make Europeans understand that there are a number of industrial and technological projects that help to strengthen the credibility of our nuclear deterrent," Tenenbaum said.
"This may enable Europeans to change their minds about what they have long considered to be a kind of French luxury, when the Americans were already offering an extended deterrent."
What is France's nuclear deterrent?
What is meant exactly when we refer to France's nuclear deterrent?
Thirty years ago, the country gave up tactical nuclear weapons and retained only two types: ballistic missiles on board its four nuclear-powered ballistic missile submarines, and airborne bombs – the nuclear missiles carried by its Rafale B fighter aircraft, the visible part of the French deterrent.
While the role of the air force is complementary to the ballistic missile submarines, in the eyes of General Jean-Patrice Le Saint, who stepped down as chief of staff of the Strategic Air Forces in the summer of 2024, airborne deterrence has specific strengths.
"The first asset is the weapon. And today's weapon is a cruise missile, the ASMP-AR. This missile is extremely fast and highly manoeuvrable. It is an extremely accurate missile," General Le Saint said.
"The second advantage of the airborne component is that it is deployed from airbases that are visible infrastructures, which makes it possible, in the context of the nuclear discussion that the president would engage in, to make his intentions clear."
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From bases at Istres, north of Marseille, Avord, in the centre of the country, and Saint-Dizier, in the east, more than 2,000 air personnel are responsible for implementing France's deterrence.
While it is impossible to recall a ballistic missile, the reversibility of an air raid is always an option – up to a point.
"From the moment the Strategic Air Forces raid is committed, the crews will continue the mission to the end," continued General Le Saint.
"But up to the point of engagement, the raid can be recalled. And so, when we look at the length of our transmission resources and the capabilities of our vectors, the Rafales combined with the A330 MRTT tankers, it is possible to fly the raid several thousand kilometres before committing to it.
"And the fact that the raid is in transit is a pretty strong signal, which, as you can imagine, gives pause for thought."
Credibility crucial
A strong signal based on credibility is at the very heart of the concept of deterrence, according to General Le Saint.
"This credibility has three dimensions. The first is political, embodied by the president of the Republic, the holder of the nuclear licence. The second is technological credibility, which is what enables us to guarantee that we are capable of designing, manufacturing and deploying weapons that are reliable and safe.
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"The third aspect is operational credibility. And there's an important point here, because credibility cannot be decreed. On the other hand, there are certain parameters that make credibility objective.
"We are credible because the crews of the Strategic Air Forces are highly trained and extremely experienced, because they conduct manoeuvres – such as the Poker exercises which, four times a year, are carried out with around 50 aircraft in an extremely realistic scenario simulating a nuclear raid."
What's more, at each Poker exercise, the spy satellites of the major powers point their antennae towards France to observe the exercise and measure the credibility of France's deterrent – a scenario that has been repeated since 1964.
This article was adapted from the original version in French. Some answers have been condensed for clarity.
