In early June 2026, the Financial Times reported that the United States is exploring whether to expand its nuclear‑sharing arrangements to additional NATO allies, with particular interest from Poland and Lithuania and potentially other Baltic states. The story drew immediate attention to the prospect of U.S. nuclear‑related infrastructure moving closer to Russia’s borders, but an important nuance lay in how officials framed the issue: discussions were said to be taking place “even as NATO allies were forced to shoulder more of the burden of conventional defence,” and any agreement to expand nuclear hosting was not described as imminent.
That juxtaposition — nuclear signalling potentially moving forward while conventional engagement is recalibrated — raises a strategic question.
What Is Actually on the Table?
The public record allows for a reasonably precise description of what seems to be discussed.
At the core lies NATO’s long‑standing nuclear‑sharing framework. Under this arrangement, U.S. B61 gravity bombs are stored under U.S. custody at a limited number of European bases and can, in a crisis, be delivered by allied dual‑capable aircraft under stringent political and technical safeguards. NATO itself does not own nuclear weapons; rather, it relies on U.S. forces forward‑deployed in Europe, complemented by the national capabilities of the United Kingdom and France.
In practice, one can think of three distinct levels of potential “eastern” nuclear participation:
- Political and planning integration
Closer involvement of eastern allies in NATO’s Nuclear Planning Group consultations, exercises and decision‑shaping — short of any physical hosting. This is already reported to be happening to some extent, and the current debate could deepen that role. - “Nuclear sharing light”
Certifying additional allied aircraft — in reality, F‑35A fighters — as dual‑capable, and investing in training, infrastructure and procedures so that these aircraft could deliver U.S. B61 weapons if required, without pre‑positioning warheads on their territory in peacetime. - Physical basing of B61 bombs
A further step would be to build new hardened storage facilities and physically deploy B61 bombs, most likely the modernised B61‑12 (not the most recent version 13), on new host territory in eastern Europe. This would entail not only major political decisions but also long‑term investments – a process measured in years rather than months.
Recent reporting suggests that U.S. officials are open, in principle, to some combination of these options, while emphasising that no decision has been taken and that any expansion would take significant time. NATO’s public line stresses that its nuclear posture is continuously reviewed and adjusted, but that nuclear weapons remain only one element of a broader deterrence and defence mix.
Understanding where the initiative comes from is key.
On the European side, eastern flank states have for many years argued that NATO’s deterrence posture must be strengthened across all domains, including nuclear. Polish governments have repeatedly signalled that Poland would be “ready” to host nuclear weapons if the Alliance decided to reinforce the eastern flank, while underlining that no such decision exists. In Lithuania, senior politicians have opened a debate on whether Article 137 of the constitution — which currently prohibits weapons of mass destruction and foreign military bases on Lithuanian territory — should be reconsidered in light of the changing security environment. The debate remains at an early stage, and any amendment would require two parliamentary votes, separated by three months, with the support of a qualified majority.
The eastern push is therefore better seen as a sustained strategic preference — grounded in proximity to Russia and Belarus. For Baltic and Polish policymakers, the combination of Russian aggression against Ukraine, hybrid operations against NATO neighbours and the deployment of Russian nuclear capabilities in Belarus has sharpened already existing concerns.
On the American side, receptivity is shaped by a broader strategic shift. Recent U.S. strategic documents and debates put increasing emphasis on deterring China in the Indo‑Pacific, defending the homeland, and demanding more “burden‑sharing” — and at times “burden‑shifting” — from European allies. European defence is framed less as a theatre of automatic American primacy and more as an area where wealthy allies must assume primary responsibility for conventional defence, while the United States provides selected enabling capabilities and a continued nuclear guarantee.
In this emerging “NATO 3.0” model, as it is sometimes described, the U.S. contribution to European security increasingly centres on nuclear and high‑end enablers, while routine conventional presence becomes more rotational, conditional and subject to regular review. Within that logic, expanding nuclear‑related cooperation with frontline allies can appear as a relatively cost‑effective way to reassure them at a moment when conventional U.S. forces in Europe are under pressure.
It is important to underline that no U.S. administration has declared a formal doctrine that replaces conventional presence in Europe with nuclear visibility. The risk is subtler: if decisions on nuclear signalling and conventional posture move in opposite directions, allies and adversaries may misread the developments.
Russia, Belarus and the Risk of Misreading
Any change in NATO’s nuclear posture will be perceived through the filter of Moscow’s strategic culture, doctrine and domestic narrative. Russian leaders routinely portray NATO’s forward‑deployed nuclear systems as destabilising and have, since 2022, intensified nuclear rhetoric in connection with the war against Ukraine.
In March 2023, President Vladimir Putin announced that Russia would station tactical nuclear weapons on Belarusian territory under a form of “sharing” arrangement, including Iskander‑M systems and modified aircraft. Russian and Belarusian officials later claimed that warheads had been transferred, while Western and independent assessments have highlighted uncertainty about the scope and operational status of the deployment.
Russian nuclear doctrine has been formally updated in recent years. New basic principles adopted in 2024 broadened the conditions under which Russia reserves the right to use nuclear weapons, from threats to “the very existence of the state” to “critical threats” to sovereignty and territorial integrity — including in relation to Belarus. Possible triggers now also include large‑scale aerospace attacks using aircraft, missiles and drones. Many Western analysts interpret the combination of ambiguous doctrine, lowered thresholds and frequent nuclear signalling as an attempt to deter Western support to Ukraine and to dissuade NATO from deeper involvement.
At the same time, there is a growing debate in Western expert circles about how to characterise Russian nuclear strategy. The popular shorthand “escalate to de‑escalate” — the notion that Moscow plans early, limited nuclear use to terminate a conventional conflict on favourable terms — has been criticised as an oversimplification that may mislead decision‑makers. It is more robust to say that Russia increasingly employs nuclear rhetoric and deployments, including in Belarus, as tools of coercive diplomacy and strategic intimidation.
From this perspective, a NATO decision to certify more eastern dual capable aircraft deployments, increase nuclear‑related exercises in the region or actually base B61‑12 bombs closer to Russian territory would almost certainly be framed by the Kremlin as justification for counter‑measures. Moscow would present such steps as confirming its narrative of encirclement and as grounds for additional deployments or exercises, including in Belarus.
The concern is not only a predictable propaganda spiral. In a crisis, changes in basing patterns and force posture on both sides could increase the risk of misperception and compress decision‑times, especially if new storage sites and dual‑capable units on the eastern flank are seen as high‑value targets for pre‑emptive conventional, cyber or sabotage attacks.
France’s Forward Deterrence and the British Dimension
A parallel variable is the evolution of the French and British nuclear role in Europe.
France maintains its own independent nuclear arsenal and does not participate in NATO’s Nuclear Planning Group. For decades, French doctrine has emphasised national sovereignty and “strict sufficiency”, yet recent political and strategic developments have pushed Paris to articulate more clearly the European dimension of its deterrent. In March 2026, President Emmanuel Macron announced a doctrine of “forward deterrence” (dissuasion avancée), under which France will modestly increase its number of warheads, stop publishing aggregate stockpile numbers to maintain strategic ambiguity, and open new channels for consultations, exercises and temporary deployments with European partners.
Under this concept, French nuclear‑armed aircraft could, in a crisis or for exercises, be forward‑based on allied European territory, including in northern Europe, while full operational control and decision‑making authority would remain exclusively with Paris. There is no dual‑key system, no nuclear sharing in the NATO sense, and no delegated authority to partners. Rather, France positions its deterrent as a European contribution that can be brought closer to partners’ territory when needed — a complement, not a replacement, to the U.S. extended nuclear deterrent.
The United Kingdom has an independent submarine‑based deterrent and has deepened nuclear‑related cooperation with France. In the Northwood Declaration of 2025, London and Paris stated that their forces are independent but can be coordinated, and created a Nuclear Steering Group to develop shared planning assumptions and coordinated patrols. At the same time, the UK has decided to procure F‑35A aircraft to participate in NATO’s dual capable aircraft mission, implying closer integration with U.S. nuclear systems and reopening the question of hosting B61‑12 I Britain.
Taken together, these developments point toward a more complex and multi‑layered European nuclear landscape: U.S. nuclear sharing, French forward deterrence and a growing Franco‑British coordination mechanism now interact in ways that both broaden deterrence options and complicate governance.
For policymakers in Warsaw, Vilnius and other eastern capitals, the question is therefore no longer only how far U.S. nuclear sharing should extend, but also how that framework will coexist with French initiatives, with a changing British role and with broader European debates on strategic autonomy.
Any move to expand nuclear sharing eastward inevitably intersects with a global non‑proliferation regime that is already under severe strain.
New START, the last bilateral agreement limiting U.S. and Russian strategic nuclear forces, expired in February 2026. For the first time since the early 1970s, there are no legally binding limits on their deployed strategic arsenals. At the multilateral level, the eleventh NPT Review Conference in spring 2026 ended without consensus — the third consecutive failed review. The core NPT bargain — disarmament in exchange for non‑proliferation — looks more under strain than at any time in recent decades.
Within this fragile context, NATO’s existing nuclear‑sharing arrangements already attract criticism. The United States and its allies (and from the start also the Soviet Union) argue that these arrangements are compatible with the NPT because U.S. nuclear weapons remain under U.S. custody and control in peacetime, and any transfer of control would only occur in war, when the NPT would in practice no longer be in force. Critics — not least supporters of the Treaty on the Prohibition of Nuclear Weapons (TPNW) — dispute this interpretation, arguing that hosting nuclear weapons and preparing for their joint use undermines both the spirit of the NPT and the emerging TPNW norm.
Today, five European NATO states continue to host an estimated 100 U.S. B61 bombs, while infrastructure is being upgraded at RAF Lakenheath. Russia’s deployment of tactical nuclear weapons in Belarus has added a new and deeply troubling non‑NATO example of nuclear sharing, which Moscow explicitly presents as mirroring NATO practice.
An eastern expansion of nuclear sharing would not constitute proliferation in the strict sense — no new state would formally become a nuclear‑weapon state. But it would deepen arrangements that are already politically contested and would likely be used by Russia, China and parts of the Global South to portray the West as inconsistent on non‑proliferation.
For Europe this reputational risk is not trivial. As bilateral agreements collapse and the NPT review process falters, any step that is perceived as expanding the role or footprint of nuclear weapons adds to the burden on an already fragile normative structure.
The core strategic challenge is coherence across the conventional–nuclear spectrum, at a time when both pillars are in flux.
NATO’s nuclear sharing was originally conceived as part of a broader system of forward‑based conventional forces and integrated planning, designed to ensure that nuclear weapons remained a last resort rather than a substitute for credible conventional defence. This logic underpinned the Alliance’s posture during the Cold War and survived into the post‑Cold War era.
Today, the picture is more mixed. On the one hand, European allies have increased defence spending, several have passed the two‑per‑cent benchmark and some — especially on the eastern flank — plan historically high investments. On the other hand, U.S. posture reviews and concrete decisions point toward reductions in some conventional commitments in Europe, especially rotational land and air units, as Washington shifts resources and political attention to the Indo‑Pacific.
It is against this backdrop that talk of expanded nuclear sharing on the eastern flank acquires its real significance. Several interlocking risks stand out:
- Perceived substitution
Even if U.S. and NATO officials insist that nuclear and conventional deterrence are complementary, coinciding nuclear moves and conventional drawdowns can be read as a functional trade — “nuclear forward, conventional back.” For eastern allies facing daily hybrid pressure, drone incursions, sabotage and disinformation, an Article 5 guarantee perceived as more nuclear‑heavy and less conventionally grounded may not reassure; it may raise doubts about the Alliance’s willingness and ability to act effectively below the nuclear threshold. - Operational vulnerability
New storage sites, air bases and dual capabile units in Poland or the Baltic states would become high‑priority targets in a crisis. In a region with limited strategic depth, this increases incentives for pre‑emptive action — conventional, cyber or via sabotage — and complicates escalation management on both sides. The more rungs are added to NATO’s nuclear ladder in a geographically exposed theatre, the more complex crisis management becomes.
None of this means that expanded nuclear sharing on the eastern flank is doomed to fail. It does mean that its success or failure will depend less on technical implementation than on whether it is embedded in a broader strategy that restores coherence rather than deepens fragmentation.
If extended nuclear sharing is firmly anchored in a sustained European effort to build robust conventional forces, resilient societies and credible non‑nuclear escalation management, it could underscore that NATO’s entire escalation ladder — from hybrid response to nuclear backstop — is both credible and controlled. If, by contrast, nuclear initiatives are perceived as a substitute for conventional presence or as symbolic gestures in lieu of serious European capability development, they may be read — in Moscow, in eastern Europe and globally — as a sign of retreat.
Lars-Erik Lundin