Lithuania Votes to Lift Constitutional Ban on Foreign Military Bases and Nuclear Weapons

Article 137 states that weapons of mass destruction and foreign military bases may not be stationed on Lithuanian territory. The provision was adopted in 1992, when the overriding security question was how to prevent the return of foreign forces after decades of Soviet occupation.

That logic has not simply become obsolete. It has been reversed.

Lithuania is now a NATO member on the Alliance’s eastern flank, bordering Belarus and close to Russia’s Kaliningrad region. Its government and parliamentary supporters argue that a constitutional prohibition designed to prevent foreign military deployments has become a constraint on collective defence.

The timing is inseparable from Russia’s military integration with Belarus. Moscow has moved non-strategic nuclear capabilities into Belarus, while the Russian Oreshnik intermediate-range ballistic missile system was deployed there in December 2025. In May 2026, Russian and Belarusian forces conducted exercises involving the simulated use of tactical nuclear weapons. The Belarusian deployment has therefore changed the geography in which Lithuania assesses deterrence.

Lithuanian officials have also pointed to the fact that Poland, Latvia and Estonia do not have equivalent constitutional prohibitions. From Vilnius’s perspective, the question is increasingly not whether NATO can reinforce the Baltic region, but whether Lithuania’s own legal framework leaves it with fewer options than its allies.

That distinction matters.

The amendment would not order NATO to station nuclear weapons in Lithuania. It would remove a domestic legal barrier that currently prevents such a decision from even being considered within the country’s constitutional framework.

The January vote is more important than September’s

The September 22 vote was a significant political step, but it did not amend the constitution.

Lithuanian constitutional procedure requires two formal adoption votes, each supported by at least 94 of the 141 members of the Seimas. The first is scheduled for October 6, with the final vote planned for January 12, 2027, after the mandatory three-month interval.

That makes the next four months more consequential than the headline vote itself.

The 99 votes secured on September 22 provide a substantial starting point, but the amendment still has to clear the two-thirds threshold twice. The process also gives opponents time to challenge the strategic rationale and allows the government to define what removing Article 137 would actually mean.

The broader legislative context is also important. The constitutional proposal forms part of a much larger package of roughly 550 defence, security and demographic measures that Lithuania wants to advance during the current parliamentary term. The repeal is therefore not an isolated nuclear initiative, but part of a wider attempt to reshape the country’s security architecture.

A legal change is not a nuclear deployment

The most important distinction in the debate is between eligibility and capability.

Removing Article 137 would make nuclear sharing legally possible under Lithuanian domestic law. It would not produce a nuclear-sharing arrangement automatically.

NATO’s existing system is based on political decisions, specialised infrastructure, certified aircraft, trained personnel and procedures involving the Alliance’s Nuclear Planning Group. Existing arrangements include US B61 nuclear bombs in Belgium, Germany, Italy, the Netherlands and Turkey.

A Lithuanian nuclear role would therefore require decisions well beyond Vilnius. NATO would have to agree to such a change, while the United States would have to authorise the relevant nuclear arrangements. Lithuania would also need specialised storage and security infrastructure, upgraded airfields, suitable dual-capable aircraft and trained crews and security personnel.

Even with political approval, building and certifying such a system would take years. The realistic timeframe identified for the necessary infrastructure is roughly two to four years, putting any physical deployment well beyond the constitutional process itself.

The September vote should therefore be read as preparation for an option, not evidence that nuclear weapons are about to arrive in Lithuania.

That difference is particularly important because the political signal can travel much faster than the military capability.

The old NATO-Russia formula is becoming harder to sustain

The deeper issue is what Lithuania’s move says about the assumptions that shaped NATO’s post-Cold War expansion.

In the 1990s, NATO sought to reassure Moscow that enlargement would not be accompanied by a comparable eastward expansion of nuclear infrastructure. The 1997 NATO-Russia Founding Act recorded the Alliance’s position that it had “no intention, no plan and no reason” to deploy nuclear weapons on the territory of new members, and said it saw no future need to change that posture.

That language belonged to a European security environment built around restraint, reinforcement and the expectation that large-scale confrontation between Russia and NATO could be avoided.

The military geography of 2026 is different.

Russia’s forward deployment of nuclear-related capabilities in Belarus has created precisely the kind of pressure that the post-Cold War arrangements were designed to manage without permanent nuclear movement further east. Lithuania’s response is not to announce a nuclear deployment, but to remove one of its own remaining legal constraints.

That creates a strategic tension for NATO.

The Alliance has continued to modernise and strengthen its nuclear deterrence arrangements, with its Nuclear Planning Group reaffirming in June 2026 that nuclear forces remain central to extended deterrence. But moving the physical architecture of nuclear sharing towards the Baltic region would represent a much more consequential step than simply improving existing capabilities.

Vilnius is effectively asking whether the legal and strategic architecture designed for the post-Cold War period remains sufficient when Russia has placed nuclear-capable systems and associated infrastructure much closer to NATO’s eastern frontier.

Moscow can object, but Lithuania is changing the legal equation

Russia has responded with warnings that any NATO nuclear assets in Lithuania would be treated as a direct strategic threat. Russian officials have threatened military-strategic countermeasures and described the Lithuanian initiative as irresponsible.

Those statements are politically significant, but they do not alter the immediate legal reality: Lithuania is not yet hosting NATO nuclear weapons, and the constitutional amendment does not itself authorise NATO to deploy them.

Moscow’s more difficult problem is that the measure changes the options available to Lithuania without requiring Lithuania to exercise any of them immediately.

The same applies to conventional forces.

Removing Article 137 would also remove the constitutional prohibition on foreign military bases, creating a clearer domestic framework for permanent allied infrastructure. That is relevant to Lithuania’s plans for deeper NATO integration, including the planned permanent German brigade. The constitutional change would therefore matter even if nuclear sharing never materialised.

This is where the amendment becomes more consequential than its nuclear headline suggests.

Lithuania is trying to move from a security model in which foreign military presence was constitutionally constrained to one in which permanent allied forces, infrastructure and potentially nuclear-sharing arrangements can be considered as components of the same national defence system.