Can Ukraine Legally Reclaim Its Nuclear Status?

In debates about Ukraine’s future, one question keeps resurfacing, quietly at first and then ever louder: could Ukraine ever re-enter the nuclear club? After the collapse of the security assurances that once underpinned its denuclearisation, the issue is no longer confined to fringe commentary. 

 

It now sits at the intersection of law and survival, of the NPT’s rules and a state’s right to exist. This article asks the hardest version of the question: can Ukraine legally reclaim a nuclear status, and what would such a decision mean for the world that once persuaded it to disarm?

Ukraine’s nuclear knot: how the 1990–1994 package built an architecture that broke in 2014 and 2022

1) The inheritance moment: a vast arsenal without a sovereign nuclear status

After the collapse of the USSR, Ukraine found itself hosting one of the largest nuclear arsenals in Europe. In practice, this was an unprecedented status: warheads were on Ukrainian territory, but command-and-control, permissive action links, and much of the operational chain remained embedded in Soviet, then Russian, systems.

That starting point matters. Ukraine’s decisions in 1990–1994 were not made in a moral vacuum. They were made under hard power realities and intense external pressure to preserve the global non-proliferation regime.

2) Arms control first, then non-proliferation: START I and the Lisbon Protocol

The “denuclearisation of Ukraine” was folded into a broader US–Russian arms control logic. A key milestone was the Lisbon Protocol (23 May 1992), which aligned Belarus, Kazakhstan and Ukraine with START I and anchored their trajectory towards non-nuclear status under the NPT framework.

The political meaning of Lisbon was straightforward: “we lock in a legal pathway through which post-Soviet republics exit the nuclear category”.

3) The 1994 trilateral bargain: warheads exchanged for compensation and assurances

When negotiations stalled, a US–Ukraine–Russia trilateral format emerged. The Trilateral Statement of 14 January 1994 reflected the core bargain: Ukraine would transfer warheads for dismantlement; in return, the package encompassed compensation mechanisms (including nuclear fuel arrangements) and the provision of security-related assurances.

This was not a romantic story of disarmament for peace. It was a transaction: Ukraine relinquished a strategic asset; in exchange it received a mix of technical-financial arrangements and political “insurance”.

4) The NPT: not a security guarantee, but a legal self-restraint regime

This element is often misunderstood. The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is not a collective defence instrument. It is a status treaty:

• non-nuclear-weapon states undertake not to acquire or manufacture nuclear weapons;
• nuclear-weapon states undertake not to transfer them;
• the system relies on verification and the political cost of breach.

Ukraine acceded to the NPT as a non-nuclear-weapon state and entered the IAEA safeguards system. That is not a memorandum of polite promises; it is an institutionalised verification regime.

5) The Budapest Memorandum: the bridging document between disarmament and assurances

The Budapest Memorandum (5 December 1994) became the public symbol of the deal: Ukraine joined the NPT as a non-nuclear-weapon state and surrendered the inherited arsenal; in return, the United States, the United Kingdom and Russia provided security assurances (not “guarantees” in the sense of a mutual-defence treaty).

Two structural weaknesses were effectively treated as acceptable at the time:

1. No enforcement mechanism. There is no automaticity, no Article 5, no pre-defined package of actions triggered by aggression.

2. Constructive ambiguity. The language supports political invocation of obligations, while leaving substantial room for legal interpretation. Many analysts consider this the memorandum’s original vulnerability.

“If assurances are breached, does that mean nothing applies?” What treaty law actually says

1) International law has no universal “reset button”

Even if one party commits a grave breach, that does not automatically terminate other instruments concluded under different frameworks with different parties.

The key reference point is the Vienna Convention on the Law of Treaties (VCLT, 1969). It provides for termination or suspension in response to a “material breach”, but this:

• primarily concerns legally binding treaties;
• requires procedural steps and legal reasoning;
• does not convert into a blanket release from obligations under separate instruments.

2) Budapest is contested in legal character: political commitment with legal shading

Experts disagree on whether Budapest functions as a “treaty” in the strict VCLT sense. It is recorded in the UN system, but is frequently treated as a political instrument reinforcing principles of the UN Charter and Helsinki. Legal arguments exist that it still contains obligations, but its enforcement pathways are minimal.

That leads to the uncomfortable conclusion: a breach of Budapest does not provide Ukraine with a clean legal lever that automatically voids the NPT.

3) The NPT is not legally conditional on Budapest, even if it was politically linked

Legally, the NPT operates on its own footing. Politically, Ukraine did view the 1994 package as interlinked: without assurances, accession would have been far harder to sell domestically. That political linkage is central to how the bargain is remembered and debated.

The core question: can Ukraine leave the NPT?

Yes. Article X of the NPT permits withdrawal if a state decides that “extraordinary events” have jeopardised its “supreme interests”. The procedure is stringent: notification to all parties and the UN Security Council at least three months in advance, with a statement of the events relied upon.

Crucially: the right to withdraw from a status treaty is not the same thing as an immediate capability shift. Any movement towards actual weapon acquisition would trigger severe political-economic consequences and would almost certainly fracture the coalition that currently sustains Ukraine.

I will not discuss practical pathways to weapon creation. That crosses a safety line. What can be analysed responsibly are the legal contours and the strategic consequences.

Why this architecture produced a security catastrophe

The catastrophe is not simply that Ukraine “trusted words”. The catastrophe is that the international system sent a message:

• assurances without enforcement do not stop a nuclear-armed power willing to pay the price;
• the non-proliferation regime does not compensate for an existential security risk for a state bordering a revisionist actor.

From 2014 (Crimea) and especially from 2022 (full-scale invasion), that message became global. It is now a case study: “without a hard guarantee, sovereignty is conditional”.

That is why, in recent years, the West has tried to build a “Budapest substitute”: a web of long-term bilateral security arrangements and a G7-type framework designed to lock in support across training, weapons supply, industrial capacity, intelligence co-operation and sanctions architecture.

Forecast: what happens if Ukraine stays within the non-proliferation framework

Scenario A: Ukraine remains in the NPT and seeks hard guarantees without nuclear status

Likely consequences:

1. Sustained and deepened external support. A large part of the moral and political legitimacy for assisting Ukraine rests on Ukraine remaining a “responsible” actor within non-proliferation.

2. A shift from assurances to enforceable commitments. The direction of travel is towards arrangements that are more treaty-like, more parliamentary, and more operationally specific.

3. A long but realistic path to durable security via integration. Not necessarily NATO in its classic form; it could be NATO-plus arrangements, robust bilateral pacts, and a European defence pillar.

The key risk is obvious: this pathway only works if the guarantees become genuinely enforceable. Otherwise, it becomes “Budapest 2.0” with a new label.

As of 14 December 2025, multiple reputable reports have described ongoing discussion in which Ukraine’s leadership has signalled that NATO membership could be traded for legally binding security guarantees from Western partners. If that translates into formal instruments, it would be the most significant redesign of the guarantees logic since 1994.

Scenario B: Ukraine remains non-nuclear but shifts to non-nuclear deterrence

This would mean building a deterrence posture through:

• long-range conventional strike capability,
• layered air and missile defence,
• rapid scaling of defence industry,
• asymmetric deterrence (including drones and resilience).

This does not produce an “absolute” shield, but it can raise the cost of aggression to a level that approximates the effect of an extended nuclear umbrella, especially if backed by allies.

Forecast: what happens if Ukraine withdraws from the NPT or signals a nuclear trajectory

It is essential to separate withdrawal from actual weapon pursuit. They are not the same.

Scenario C: Ukraine withdraws from the NPT (lawfully under Article X)

Likely consequences:

1. A diplomatic shock and fractures among partners. Even Ukraine’s strongest supporters are structurally invested in the NPT as the backbone of global security.

2. Intensified pressure through sanctions and conditionality.

3. Heightened risk of “preventive” actions by adversaries against critical infrastructure under a non-proliferation pretext.

A further point: withdrawal does not solve tomorrow’s battlefield security problem. It is a political signal, potentially a bargaining instrument: “either you give enforceable guarantees, or we leave”. But it is extremely dangerous leverage, because reputational damage and coalition losses could become irreversible.

Scenario D: Ukraine moves from signalling to actual nuclear acquisition

This would almost certainly:

• reframe Ukraine from “victim of aggression supported by a coalition” to “a non-proliferation crisis case”;
• force partners to distance themselves publicly or impose constraints;
• risk a regional cascade, as other states conclude that survival without nuclear status is untenable.

The paradox is stark: the pursuit of an “ultimate shield” could weaken the support that keeps Ukraine viable in the near term faster than any strategic effect could materialise.

What new alliances and alternative groupings could emerge

If the international system cannot deliver a credible non-nuclear substitute for nuclear deterrence, new structures will form. Several trajectories look plausible:

1. A European umbrella through deeper defence integration
   Not necessarily a formal “EU army”, but tighter integration of procurement, standards, logistics, air defence, pre-positioning and industrial mobilisation.

2. A network of mutual-defence-style bilateral pacts around Ukraine
   More like the US alliance model in Asia: a lattice of legally grounded bilateral arrangements with pre-specified measures, rather than one single monolithic bloc.

3. A Baltic–Black Sea security axis
   A regional coalition built around the states most directly exposed to Russian revisionism: intelligence, air defence, maritime security, resilience and joint industrial capacity.

4. Ad hoc coalitions of deterrence against “rogue” aggressors
   More “coalitions of the willing” with pre-agreed sanctions triggers, asset immobilisation frameworks, export controls and rapid military assistance pathways.

5. A technology-based shield
   A doctrine combining long-range conventional capability, drones at scale, cyber deterrence, integrated air defence, space-enabled ISR, and industrial surge capacity. If institutionalised, it could become the new non-nuclear security paradigm for exposed states.

The conclusion no one wants to state plainly

Ukraine is now a live stress test for the international order:

• If the world can provide Ukraine with real, enforceable, operational security guarantees without forcing a nuclear trajectory, the non-proliferation regime survives and may even strengthen.
• If it cannot, survival logic will increasingly overpower rules logic, and proliferation will become not a theoretical risk but a rational reaction by threatened states.

By Andrii Azarov, Professor of Business and Economics at IBA Consortium (UK)