Within 48 hours of Finland formally ending its own nuclear weapons prohibition, Lithuania moved to erase the last remaining constitutional barrier to hosting nuclear arms on NATO’s most exposed eastern flank — a coordinated posture shift arriving three days before the alliance’s leaders convene in Ankara to confront exactly the question both Baltic nations have now forced into the open: where, and in which hardware, will NATO’s nuclear deterrent actually live?
On July 2, 2026, Lithuanian President Gitanas Nausėda announced that leaders of all parliamentary factions had reached near-unanimous consensus to repeal Article 137 of the Lithuanian constitution — a clause from the country’s post-Soviet independence period that explicitly prohibits weapons of mass destruction and foreign military bases from Lithuanian soil. A bill to formally repeal the article was registered in the Seimas on July 3 with 51 co-sponsors — enough under parliamentary rules for the legislation to move forward.
The announcement came one day after Finland’s identical ban formally ceased to have legal effect, making these the two most significant nuclear posture shifts among NATO’s newest eastern members since the Cold War ended — and sending a sharp signal into the Ankara summit beginning July 7.
Article 137 Was a Clause From a Different World
Article 137 of Lithuania’s constitution prohibited not only weapons of mass destruction but also any foreign military bases on Lithuanian territory. The provision was drafted during the country’s independence transition in the early 1990s, at a moment when Vilnius wanted to distinguish its sovereignty from Soviet-era militarism and signal peaceful intent to the broader international community.
Nausėda’s framing of the clause’s obsolescence was blunt: the geopolitical situation has gotten worse, and a constitution written for a different era should not constrain a NATO member’s ability to fulfill alliance obligations. “Opinions were practically unanimous,” he told reporters after a meeting with parliamentary and government leaders. “Almost all parliamentary faction leaders expressed the view that Article 137 has become obsolete and should not merely be amended but removed.”
His reasoning: leaving even a modified version of the clause in place would impose self-restrictions that no other NATO ally faces — making Lithuania what he called a “weak link or a grey zone within NATO.”
There is one procedural dispute. Representatives of the opposition Nemunas Dawn party argued the constitutional change should be decided by national referendum rather than parliamentary vote. Nausėda, and the vast majority of faction leaders, favor giving the existing parliament the authority to act on its mandate from voters. An unnamed Lithuanian MP separately criticized the decision as having been reached “behind closed doors” without public arguments or polling.
Amending the constitution is not a fast process. From a purely legal standpoint, changing Article 137 requires a two-thirds supermajority of the Seimas voting twice, with at least three months between votes. The political signal is already sent; the legal process will take months at minimum.
Finland’s Ban Ended Hours Earlier — and Russia Responded Immediately
Lithuania’s move did not happen in isolation. Finland’s ban on the import, storage, manufacture, and use of nuclear weapons formally ended on July 1, 2026, after Finnish President Alexander Stubb signed amendments to the country’s Nuclear Energy Act in late June. The Finnish parliament had voted 125 to 61 in favor of the legislation in June — a commanding two-thirds majority that Defense Minister Antti Häkkänen called a “historic reform” that “strengthens the security of Finland and of NATO as a whole.”
Finland’s ban dated to the 1980s and covered nuclear explosives under its Nuclear Energy Act. The new law permits nuclear weapons to be brought, transported, supplied, or possessed on Finnish territory where the country’s military defense requires it — including under NATO alliance operations. Stubb and Häkkänen both emphasized that no permanent stationing of nuclear arms is planned in peacetime.
Russia’s response was immediate. Moscow announced the closure of seven railway border crossings with Finland, Estonia, and Latvia, effective July 1 — a retaliatory trade measure that leaves Finland with no open rail crossings with Russia, cutting off the fertilizer exports that had previously moved by rail.
What NATO Nuclear Sharing Actually Requires: WS3 Vaults, F-35s, and 110-Person USAF Squadrons
The diplomatic framing of Lithuania’s and Finland’s moves — “removing a legal barrier” — understates the operational and industrial reality that follows if either country enters NATO’s formal nuclear-sharing arrangement. Hosting US nuclear weapons is not a political decision that becomes operational at signing. It is a multi-year engineering and certification pipeline with specific, non-negotiable hardware requirements.
Under NATO’s nuclear-sharing framework, approximately 125 to 130 US B61-series tactical nuclear bombs are currently deployed across five Western European air bases. Each base operates a Weapons Storage and Security System — the WS3. The core component is a Weapon Storage Vault (WSV): an elevator-drive, two-story steel construction embedded underground into the floor of a hardened aircraft shelter. Each WSV holds up to four B61 bombs, and each air base typically has 11 WS3-equipped shelters, giving a maximum base capacity of 44 weapons. The infrastructure also requires underground cable networks, Alarm Communication and Display systems, and integrated command-control-communications software that must be certified before any weapons can be stored.
Security is provided by a US Air Force Munitions Support Squadron, or MUNSS — approximately 110 personnel per base — who are responsible for physical security, maintenance, and logistics, and for handing over the weapons to national air forces only if ordered to do so by the US National Command Authority. The only aircraft authorized to move US nuclear weapons between bases is the C-17A Globemaster III.
The nuclear weapons themselves remain under US custody and control. Permissive Action Link codes — the electronic authorization required to arm the weapons — stay exclusively with the US National Command Authority. No NATO ally controls a US nuclear weapon without explicit presidential authorization.
For a host nation’s own aircraft to deliver nuclear weapons under a wartime authorization, those aircraft must be certified dual-capable aircraft, or DCA. NATO’s current standard DCA is the F-35A Lightning II, which is replacing the F-16 and Panavia Tornado across the alliance. The F-35A is certified to carry the B61-12 thermonuclear gravity bomb and provides stealth penetration capability for contested airspace delivery.
This creates a structural procurement requirement. A nation that enters the nuclear-sharing DCA mission must field F-35A aircraft certified for nuclear delivery — it is not possible to participate in the mission with legacy aircraft. Eastern-flank nations currently building that fleet include Poland, which received its first three F-35A Husarz fighters in May 2026, as well as Finland, Czech Republic, and Romania.
The upgrade of an existing base to WS3 standards runs to hundreds of millions of dollars in infrastructure alone. Defense analysts from AJ Bell, reviewing the procurement implications of any eastern-flank nuclear-sharing expansion, noted that a meaningful step-up in nuclear deployment in Europe could create “big earnings opportunities” for F-35 supply chain members including Lockheed Martin, Northrop Grumman, BAE Systems, Rolls-Royce, and Cobham.
Kaliningrad Is the Strategic Reason This Is Happening Now
Lithuania holds one of the most strategically fraught positions in the alliance. To its west, it hosts NATO’s eastern battlegroup, currently anchored by a Germany-led permanent multinational force. To its southwest lies Kaliningrad — the heavily militarized Russian exclave wedged between Lithuania and Poland, home to Russia’s Baltic Fleet.
Russia permanently stationed Iskander-M nuclear-capable ballistic missile systems in Kaliningrad, a deployment confirmed by Lithuania’s own defense ministry in 2018. The Iskander-M has an operational range of up to 500 kilometers and can cover all Baltic capitals — Vilnius, Riga, and Tallinn — as well as Warsaw, and reach into Germany and Scandinavia. The missile’s dual-capable design — able to carry either a conventional or nuclear warhead — means NATO cannot distinguish the character of a launch until impact, compressing escalation decision timelines to minutes.
Lithuanian military officials have spoken openly about the exclave’s role in any future conflict. Lithuania’s strategic vulnerability is compounded by the Suwałki Gap, the 65-kilometer overland corridor connecting Poland and Lithuania that military planners consider NATO’s most vulnerable potential chokepoint — its seizure would isolate the three Baltic states from the rest of the alliance.
Moscow’s response to the Baltic nuclear posture shift was characteristically unambiguous: Russian officials have warned that any NATO nuclear infrastructure deployed closer to its borders would be treated as a direct military threat and would trigger a response.
Washington’s Confidential Nuclear Expansion Review
Lithuania’s announcement lands in the middle of a confidential US review of its nuclear posture in Europe. In June 2026, the Financial Times reported that Washington is engaged in highly confidential discussions about whether to extend the nuclear-sharing arrangement to additional NATO members on the eastern flank — the first potential geographic expansion of the program since the Cold War. Poland and several Baltic nations have shown the most interest in an expansion, according to sources briefed on the discussions.
Under the current arrangement, six NATO members — the UK, Germany, Italy, the Netherlands, Belgium, and Turkey — participate in the nuclear-sharing arrangement and are approved to host US dual-capable aircraft capable of deploying nuclear weapons. A NATO official told CNBC that the organization “continuously monitors” the security environment and adapts as needed, adding that assessments of NATO’s nuclear deterrence posture have been ongoing for several years and are not linked to any specific decision on US conventional force adjustments. Any formal expansion of the arrangement would require political consensus among all 32 NATO allies, plus the multi-year WS3 and F-35A infrastructure pipeline described above — meaning even a political agreement made at Ankara in July 2026 would not produce operationally deployed weapons for years.
The discussions are partly driven by a need to reassure eastern European allies of Washington’s enduring commitment to nuclear deterrence even as the US scales back some conventional deployments and pushes allies to shoulder more responsibility.
Macron’s Parallel Track — and Why the Baltics Are Not on His List
A second nuclear deterrence track has been running in parallel since March 2, 2026, when French President Emmanuel Macron announced what he called “dissuasion avancée” — forward deterrence — from the Île-Longue submarine base. Macron announced France would increase its nuclear warhead stockpile for the first time since 1992, stop disclosing the total size of its arsenal, and allow forward-basing of nuclear-capable Rafale B aircraft in partner countries during a crisis.
Notably absent from that list: Estonia, Latvia, Lithuania, Norway, and Finland — countries that directly border Russia. The Atlantic Council’s analysis noted the absence, observing that it “underscores the enduring limitations of France’s nuclear posture as an extended deterrent” for the nations most exposed to Russian aggression. France retains sole command and control authority over its weapons under its constitution; partners cannot share in deployment decisions.
France’s framework offers one operational advantage the US track does not: a host nation can receive temporary Rafale B deployments during a crisis without purchasing French aircraft — making it a lower entry point than the US B61/F-35A DCA pipeline that requires domestic aircraft procurement.
What the Ankara Summit Must Answer
Heads of state and government from all 32 NATO members are scheduled to gather in Ankara on July 7–8, 2026. NATO Secretary General Mark Rutte has framed three summit priorities: increasing allied defense investment, bolstering transatlantic defense industrial production, and supporting Ukraine. A pre-negotiated Ankara Declaration — agreed at ambassador level before leaders arrived — reaffirms collective defense under Article 5, commits to €70 billion in additional Ukraine support, and declares that “Iran can never have a nuclear weapon,” according to Euronews reporting.
Nuclear deterrence posture is expected to be among the summit’s most sensitive agenda items, though formal decisions on nuclear-sharing expansion are not anticipated. The summit arrives as at least four Baltic and eastern European allies — Estonia, Latvia, Lithuania, and Poland — are already allocating more than 3.5 percent of GDP to core defense spending, ahead of the alliance’s timeline.
Nausėda used a pre-summit press conference in Berlin with the presidents of Latvia and Estonia and German Chancellor Friedrich Merz to issue a pointed warning: NATO risks splitting into two or three groups if member states that have committed to the 5 percent GDP defense spending target — agreed at the 2025 Hague summit — fail to follow through. “This will negatively affect the spirit of collective defense within NATO and undermine allied solidarity,” he said.
Lithuania’s Defense Minister Robertas Kaunas has specified that any deployment of US nuclear weapons in Lithuania would be considered only during a crisis or wartime — the same framing Finland’s government used before its ban was lifted. That framing — “not now, but never is off the table” — is now embedded in the constitutional architecture of two NATO states on Russia’s border.
Whether Washington, or Paris, acts on the cleared legal landscape — and on what timeline — is a question the Ankara summit may begin to frame, even if only behind closed doors. What is already determined, by both the hardware requirements of nuclear sharing and the years of certification and construction they demand, is that the question will not be answered quickly.
Frequently Asked QuestionsWhat is NATO nuclear sharing, and how does it actually work?
NATO’s nuclear-sharing arrangement allows non-nuclear alliance members to participate in the planning and potential delivery of US nuclear weapons without those countries acquiring or controlling the weapons themselves. The US deploys approximately 125 to 130 B61-series tactical nuclear bombs at five Western European air bases, stored in hardened WS3 vault systems. Host nations provide certified F-35A dual-capable aircraft and trained crews; the US retains physical custody of the bombs and holds the Permissive Action Link codes that must be electronically authorized before any weapon can be armed. Delivery by allied aircraft would only occur after explicit authorization from the US president. The arrangement has been in place since the 1960s and currently involves six NATO members: the UK, Germany, Italy, the Netherlands, Belgium, and Turkey.
What would it actually take for Lithuania to host US nuclear weapons?
Far more than a constitutional amendment. Hosting B61 bombs under the NATO nuclear-sharing arrangement requires constructing Weapon Storage Vault infrastructure inside hardened aircraft shelters — each vault holds up to four bombs, requires elevator-drive mechanisms and integrated alarm and command systems, and must be certified to USAF standards. An air base typically needs 11 such shelters for a capacity of 44 weapons. Lithuania would also need to field F-35A dual-capable aircraft certified for nuclear delivery — there is no shortcut using legacy aircraft. A USAF Munitions Support Squadron of approximately 110 personnel would need to be permanently co-located at the host base. Finally, pilots must be trained through NATO’s annual Steadfast Noon nuclear exercises. From political agreement to operational capability typically spans multiple years and costs in the billions per base. Lithuania’s constitutional amendment, if passed, clears only the first legal barrier.
Will the US deploy nuclear weapons to Lithuania or Finland in the near term?
Both governments have said that any such deployment would only occur during a crisis or wartime. US officials have acknowledged confidential discussions about potentially extending nuclear-sharing arrangements to eastern-flank NATO members, but have stated no decision is imminent and that any formal expansion would require political consensus among all 32 allies. The infrastructure pipeline — WS3 vaults, F-35A procurement, MUNSS deployment — means that even a political agreement today would not produce an operationally deployed capability for several years.
Which countries currently host US nuclear weapons under NATO sharing?
Six NATO members currently participate in nuclear-sharing arrangements: the United Kingdom, Germany, Italy, the Netherlands, Belgium, and Turkey. Weapons are stored at six air bases: Kleine Brogel (Belgium), Büchel (Germany), Aviano and Ghedi (Italy), Volkel (the Netherlands), and Incirlik (Turkey), with an additional WS3 site reportedly active at RAF Lakenheath in the UK following B61 redeployment in 2025. All B61 bombs remain under US custody and control regardless of which country’s soil they rest on.