Nancy and the politics of deterrence: reading the French atomic offer to Poland

The Treaty of Nancy was signed on May 9th 2025, on Europe Day, by Donald Tusk and Emmanuel Macron in the Lorraine city where Stanisław Leszczyński, the deposed Polish king turned French son-in-law, lived out his exile. Undoubtedly, the ceremony was shrouded in the symbolism of intertwined history. The paper replaced the outdated 1991 relationship agreement (and another subsequent partnerships) and joined the tiny set of first-tier bilateral pacts France maintains with Germany, Italy and Spain – the first specified pact, in this case, with a country that does not share a border. Its safety clause commits each side to assistance in the event of armed aggression. In turn, the Polish-French Day of Friendship, fixed by the treaty for April 20th, marks the date Maria Skłodowska-Curie was interred in the Panthéon in 1995.

Ratification followed through the autumn and winter, and the treaty entered into force on January 22nd 2026. Six weeks later, on March 2nd, Macron travelled to the Île Longue submarine base close Brest and, with the SSBN Le Téméraire behind him, announced what he called “dissuasion avancée” or forward deterrence. Paris would grow its atomic arsenal for the first time since 1992, cease publishing full stockpile figures, let the temporary forward-basing of nuclear-capable aircraft on allied territory, and open structured cooperation on deterrence with 8 European partners: the United Kingdom, Germany, Poland, the Netherlands, Belgium, Greece, Sweden and Denmark. Norway joined as the ninth partner in late May 2026. Final decision authority would remain, Macron emphasized, with the French president alone.

Seven weeks later, the first Polish-French Intergovernmental Summit was convened in Gdańsk. Tusk and Macron told reporters that the 2 governments would now decision toward joint exercises, including elements of atomic deterrence. That last element, the 1 Polish media seized on most enthusiastically, is besides the 1 resting on the most fragile foundations.

Dissuasion avancée: cooperation, not coverage

What Macron announced at Brest is precisely what its French name suggests: dissuasion avancée, a forward extension of deterrent posture alternatively than a transfer of deterrent commitment. France will licence the temporary forward-basing of nuclear-capable aircraft on allied territory, grow the structured dialog on doctrine to 8 European partners, and invitation participation in exercises that simulate strategical missions. What it will not do, and what Macron took care to underline at Île Longue, is share decision authority. There is no co-decision mechanism, no permanent French atomic presence on allied soil, and no equivalent of NATO atomic sharing under which American B61 weapons are stationed on the territory of 5 European states with dual-key consent and locally based transportation aircraft. The offer sits, deliberately, in a category of its own: a tighter commitment than the implicit Article 5 atomic umbrella that the United States extends to all NATO members, but well short of the formal sharing arrangement that Belgium, Germany, Italy, the Netherlands and Turkey keep with Washington. Poland sits in neither of those categories today, and Macron’s offer does not aim to match either set up.

The umbrella imagery that dominated Polish reporting after Gdańsk overstates what Brest actually contains. Measured against either atomic sharing or an Article 5 commitment, what Paris is offering is structured cooperation: meaningful, but in a category that does not amount to atomic deterrence in the strict sense. France inaugurated its atomic Steering Group with Sweden in Paris on April 23rd 2026, 3 days after the Gdańsk summit, utilizing the same template established with Berlin and London. Stockholm, a non-nuclear state and a NATO associate only since March 2024, now sits in an organization category Warsaw does not. The Gdańsk joint declaration signals the intention to establish a high-level bilateral strategical dialog on deterrence covering both conventional and atomic dimensions. However, the form of this dialog has not yet been specified.

Domestic responsibility lines

For the Nancy framework to get genuine strategical weight, Polish commitment must hold across changes of government. At present, that condition is not full met. Nawrocki and his Bureau of global Policy have argued publically that Poland should prioritize inclusion in the American atomic Sharing programme, and have questioned whether the French arsenal is large adequate to supply a credible umbrella. Tusk’s government, while pursuing the French track, has been careful to frame it as an addition alternatively than an alternative: Warsaw is not replacing the American umbrella with a French one, but adding a layer below it. The choreography of Gdańsk reflected the same divide. The president was absent, the venue chosen outside Warsaw, and afterwards the 2 camps gave contradictory accounts of why, making the visit the latest episode in a long-running home power struggle. The constitutional reading is unambiguous: abroad policy is the prerogative of the government, not the president. Paris, in line with that reading, has built the partnership with the government, not with the Polish state in its organization fullness. The choice has the merit of pace. However, it carries a corresponding hazard that a structure built with 1 side of a home divide is more susceptible should that side lose an election.

The mirror image of this problem can be seen in Paris. The treaty was signed by a French president whose mandate ends in 2027. Marine Le Pen, leading the National Rally for over a decade, was barred from moving in March 2025 following an embezzlement conviction. Her appeal is expected on July 7th 2026. In her place, Jordan Bardella has emerged as the likely RN candidate and, since autumn 2025, has been the consistent leader in first-round polling at around 35 per cent. Le Pen has stated that the French deterrent should proceed to only defend the country by itself. Bardella’s stance seems more nuanced: he accepts that French vital interests have a European dimension, but has set out 3 red lines on the atomic question (no sharing, no co-financing, no co-decision on the button) of which only the 3rd aligns with what Macron stated at Brest. The another 2 are little clearly delineated, and could be applied narrowly or utilized to constrain the kind of structural deepening on which bilateral cooperation depends.

Domestic concerns will likely dominate the 2027 campaign, but should abroad policy intrude, it will do so through Russia and European defence. The candidates’ positions will then track the temper in France alternatively than the calculations of allies. Macron, for his part, appears to be moving deliberately to entrench arrangements his successor would find hard to reverse. Whether way dependencies of integration would constrain a Bardella presidency in practice is contested. What is not contested is that the Nancy Treaty was negotiated by 2 leaders, both of whom face uncertain political horizons.

Beyond the declarations

If the offer has limits, what underpins it is not only paper. The clearest concrete demonstration of this came after Russian drones violated Polish airspace on the night of September 9th and 10th 2025. The next day, with Poland having invoked Article 4 of the North Atlantic Treaty, Macron announced the deployment of 3 Rafale aircraft to reenforce the protection of Polish territory and NATO’s east Flank, coordinating the decision with the Alliance and with British Prime Minister Keir Starmer. The aircraft arrived under the fresh NATO Operation east Sentry. The deployment was reactive and limited, operating below the threshold of open conflict, but it was the first concrete instance in which the political logic that Nancy would later codify translated into French deployed assets in Polish skies. The category Paris uses for deeper engagement with non-nuclear partners – “dialogue de dissuasion” – has its own operational content: structured exchange on doctrine, joint exercises, and, in conditions of genuine threat, the deployment of French Rafale aircraft, themselves capable of carrying atomic weapons, in allied airspace as a signal of resolve. In addition, according to Defence24, talks are under way to bring Poland in as an observer to Operation Poker, the quarterly atomic strike exercise of the Forces Aériennes Stratégiques – a position only British representatives presently hold.

Beyond the deterrence dimension, the partnership is acquiring an industrial weight that may substance more in the average word than any single declaration. In artillery, Eurenco, the French explosives and propellants manufacturer, is investing about 250 million euros in a joint venture with Polska Grupa Zbrojeniowa to build a propellant and modular charge facility in Pionki. The task contributes to the wider European effort to close ammunition shortages, with production expected to begin in 2028. In the air, Poland is advancing plans to get 2 Airbus A330 MRTT aircraft, with an option for 2 more, and deliveries expected from 2029 onwards (though this is simply a pan-European Airbus programme alternatively than a strictly French one). In space, the 2 high-resolution Pléiades Neo reconnaissance satellites Poland contracted from Airbus Defence and Space in 2022 are now being integrated in Toulouse for launch by 2027. The first cohort of Polish operators completed their training there in late 2025. The civilian atomic track is moving in parallel from declaration toward contract: the Cooperation Plan signed alongside Nancy in May 2025, the selection of the French Arabelle turbine for Poland’s first atomic plant, and EDF’s competitive dialog for the second-site task all sit downstream of the same logic. Gdańsk itself added 2 further tangible commitments. The first was an industrial cooperation agreement signed at the summit by Airbus Defence and Space, Thales Alenia Space and the Polish RADMOR to make a geostationary military communications satellite for the Polish Ministry of National Defence. This was agreed as part of the EU’s Readiness 2030 framework in the presence of Polish Defence Minister Władysław Kosiniak-Kamysz and French Minister of the Armed Forces Catherine Vautrin. The second agreement was the joint declaration committing Poland to its first participation in the French ORION exercise in 2026, and France to renewed participation in the Polish DRAGON exercise in 2027.

What these arrangements buy is not a substitute for organization architecture but partial insulation against the political calendar. Industrial commitments, signed contracts, satellites already in integration, ammunition lines under construction – these are agreements that last elections more reliably than political pledges of intent. They do not last them perfectly: a sufficiently determined successor in either capital can slow procurement, defer next steps, or quietly let cooperation drift. But the cost of doing so rises with the volume of material commitment already in place. To the degree that the year between Nancy’s entry into force and France’s next presidential election is utilized to multiply specified commitments, the partnership acquires a kind of durability that declarations alone cannot generate: weight, and the habit of cooperation that weight produces.

Racing the calendar

Russia is the immediate reason Nancy was negotiated, but not the only one: it answers both a threat from the east and a increasing uncertainty to the west, as Washington’s commitment to European defence looks little dependable than it erstwhile did. Whether what is being built actually deters inactive depends, first of all, on how Moscow reads it. For Europe, the central fact is that each layer of European defence cooperation raises the costs of aggression on the east Flank. The drone incursions of September 2025 were a probe that aimed to test this situation. The consequence of 3 Rafales over Polish skies was an answer Moscow registered. Yet the Kremlin watches the political calendar in Paris and Warsaw as closely as the terms of the agreements. The 2027 elections offer Russia an chance it has utilized before: to push outcomes towards candidates whose triumph would weaken European defence ties, narrow support for Ukraine, and slow the organization deepening it would like to interrupt. Paradoxically, each specified effort, whether against airspace or against the ballot, has so far accelerated the very dynamic it was meant to weaken.

None of the commitments accumulating around Nancy individually amounts to a strategical alliance, but together they form a structure that, if developed further, becomes increasingly hard to dismantle. What the next 12 months will decide is not whether France will extend its deterrent over Poland, which it has signalled it will not, but how much of this material becomes contractually binding, operationally embedded, and institutionally anchored before the political calendar intervenes. While the 2 governments’ interests align, the window must be utilized to its limit. all contract signed, all exercise embedded, and all commitment locked in is simply a unit of deterrence on the east Flank that survives whoever takes office in 2027.

Nicole Czaplinska is an independent writer with a peculiar interest in armed conflicts, NATO, and defence policies. Her professional experience includes policy analysis, political affairs at the Polish Embassy in Paris, and reporting from Beirut.

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