The Budapest Memorandum and the Nuclear Arsenal Ukraine Gave Up

The summit in Budapest on December 5, 1994 was mostly about renaming things. Leaders of the Conference on Security and Co-operation in Europe, the Cold War-era forum that had brought East and West to the same table, met in the Hungarian capital and decided to turn their conference into an organization, the OSCE, with a secretariat and a budget. The press covered the name change, the speeches and a sharp public exchange between Presidents Bill Clinton and Boris Yeltsin about NATO expansion. On the margins, four leaders signed a short document a few paragraphs long. President Leonid Kuchma of Ukraine, Clinton, Yeltsin and British Prime Minister John Major put their names to a memorandum on security assurances in connection with Ukraine's accession to the Treaty on the Non-Proliferation of Nuclear Weapons. The same day, Ukraine formally joined that treaty as a state without nuclear weapons. The document had no grand title. Almost everyone now calls it the Budapest Memorandum, and almost everyone who has invoked it since 2014 has felt betrayed by it.

In short: When the Soviet Union collapsed, Ukraine was left with the world's third-largest nuclear arsenal on its soil. In exchange for sending the warheads to Russia and joining the Non-Proliferation Treaty, it received in 1994 political assurances, not binding guarantees, that the US, UK and Russia would respect its borders and refrain from force. Russia broke those assurances in 2014 and 2022, and the episode now shapes how every country weighs the bargain of giving up nuclear weapons.

An arsenal nobody planned

In 1991, Ukraine woke up as an independent country with around 1,900 strategic nuclear warheads on its territory, mounted on intercontinental ballistic missiles in silos and carried by long-range bombers, plus thousands of smaller tactical nuclear weapons. On paper that made it the third-largest nuclear power on earth, behind only the United States and Russia.

The paper was misleading. The weapons had been built, deployed and controlled by the Soviet military from Moscow. The codes and the systems that allowed a launch remained under Russian control. Ukraine had the hardware and the soldiers guarding it, but not the ability to use it on its own, at least not without years of effort. The tactical weapons were moved to Russia by the spring of 1992, before Kyiv had settled what it wanted.

The strategic weapons were a different matter. Ukrainian politicians in the early 1990s were divided. Some saw the arsenal as a burden: expensive to maintain, dangerous as it aged, and a barrier to Western aid and recognition. Others saw it as the only real security a new state could have next to a much larger neighbour that had never fully accepted its independence. Crimea, with its large ethnic Russian population and the Black Sea Fleet in Sevastopol, was already a source of tension.

The bargain, step by step

The path from inheritance to Budapest ran through three agreements.

In May 1992 in Lisbon, Ukraine, Belarus and Kazakhstan signed a protocol to the US-Soviet Strategic Arms Reduction Treaty, START I, that made them parties to the treaty alongside Russia and committed them to join the Non-Proliferation Treaty as non-nuclear-weapon states "in the shortest possible time."

Ukraine's parliament hesitated. It ratified START in late 1993 with conditions, demanding security guarantees and compensation. That led to a Trilateral Statement signed by Clinton, Yeltsin and Ukrainian President Leonid Kravchuk in Moscow in January 1994. Under it, Ukraine would transfer its warheads to Russia for dismantlement; Russia would compensate Ukraine with fuel for its nuclear power plants, derived from the highly enriched uranium in the weapons; and the United States would provide funds for the dismantling under the Nunn-Lugar Cooperative Threat Reduction programme, a bipartisan initiative begun by Senators Sam Nunn, a Democrat, and Richard Lugar, a Republican, in 1991. The statement also previewed the security assurances.

In November 1994 Ukraine's parliament voted to accede to the Non-Proliferation Treaty, and in December came Budapest. The last nuclear warheads left Ukraine in 1996. Missile silos were destroyed in the following years, and bombers were scrapped or transferred. Belarus and Kazakhstan, which had made the same commitment, also gave up the weapons on their soil.

What the memorandum promised, and what it did not

The text of the Budapest Memorandum is short, and its precise wording matters, because the difference between what people think it said and what it said is the whole story.

The United States, the United Kingdom and Russia reaffirmed their commitment to respect Ukraine's independence, sovereignty and existing borders, in line with the principles of the 1975 Helsinki Final Act. They reaffirmed their obligation to refrain from the threat or use of force against Ukraine's territorial integrity or political independence, and said none of their weapons would ever be used against Ukraine except in self-defence or otherwise in accordance with the UN Charter. They promised to refrain from economic coercion aimed at subordinating Ukraine's rights to their own interests. They committed to seek immediate action by the UN Security Council to provide assistance to Ukraine if it became a victim of aggression, or the object of a threat of aggression, "in which nuclear weapons are used." They promised not to use nuclear weapons against Ukraine except in narrow circumstances. And they agreed to consult if a situation arose that raised a question about these commitments.

Read that list again and notice what is missing. There is no promise to defend Ukraine. There is no mutual defence clause like NATO's Article 5. The Security Council commitment applies only to aggression involving nuclear weapons, and the Council is a body on which Russia holds a veto. Most of the paragraphs reaffirm obligations the signatories already had under the UN Charter and the Helsinki Final Act. And the memorandum was not a treaty ratified by the US Senate. It was a political commitment.

The word in the title, assurances, was deliberate. American negotiators were not willing to offer guarantees that would commit the United States to fight for Ukraine, and Senate ratification of such a commitment was not on the table. Ukrainian negotiators knew this. They took what they could get, in a moment when the alternative, isolation and pressure from both Washington and Moscow, looked worse.

France and China, the other two nuclear powers recognized by the NPT, gave Ukraine separate, similar assurances in their own documents.

2014, 2022 and the arguments over who broke what

In February 2014, after months of protest in Kyiv, President Viktor Yanukovych fled the country. Within weeks, Russian forces without insignia took control of Crimea, and Russia annexed the peninsula after a referendum held under occupation that Ukraine and most of the world did not recognize. Fighting then broke out in the eastern Donbas region, with Russian support for separatist forces and, later, Russian regular troops. In February 2022, Russia launched a full-scale invasion.

The violation of the memorandum's first two paragraphs seems obvious: Russia did not respect Ukraine's existing borders and did use force against its territorial integrity. Russia's government has offered several defences over the years. It has argued that the memorandum did not oblige it to accept what it called an unconstitutional seizure of power in Kyiv in 2014, that the people of Crimea had exercised self-determination, and that Western economic pressure on Russia and Ukraine's own policies were themselves contrary to the spirit of the document. Hardly any international lawyers outside Russia have found these arguments persuasive. The UN General Assembly affirmed Ukraine's territorial integrity in a resolution in March 2014, and in 2022 it demanded that Russia withdraw.

What about the other signatories? The United States and the United Kingdom did not use force against Ukraine or coerce it, so in a narrow sense they kept their own promises. They did call for consultations, and they did take the matter to the Security Council, where Russia vetoed a resolution on Crimea. Whether they did enough is a political judgment, not a legal one. They never promised to defend Ukraine, but many Ukrainians, and many in the West, felt that the spirit of the 1994 bargain implied more than they delivered, at least until the large-scale military aid that followed the 2022 invasion.

At the Munich Security Conference in February 2022, days before the invasion, President Volodymyr Zelensky said Ukraine would seek consultations under the memorandum and warned that if they failed, Ukraine would have the right to conclude that the security assurances of 1994 were not working. The consultations did not prevent the war.

Could Ukraine have kept the bomb?

This is the question everyone asks, and it deserves a careful answer rather than a slogan.

In 1993 the political scientist John Mearsheimer argued in Foreign Affairs that Ukraine should keep a nuclear deterrent, precisely because he expected Russia one day to threaten it. In the same issue, Steven Miller made the opposite case, warning that a nuclear Ukraine would face isolation, economic collapse and dangerous instability. The debate looks different with hindsight, but both sides made serious points.

Against the idea that Ukraine could simply have kept the weapons: it did not control the launch codes; the missiles were designed for Soviet targeting and required Russian maintenance; and building an independent arsenal would have taken years, enormous expense the country could not afford in the 1990s, and the hostility of both the United States and Russia, possibly including sanctions. A Ukraine that defied the NPT might have been treated as a pariah, without the Western aid and integration it sought.

For the idea that something important was lost: even a residual or latent nuclear capability might have made Moscow more cautious, and the decision was taken in exchange for promises that turned out to be weak.

The fairest conclusion is probably that keeping the arsenal was never as easy as it looks in retrospect, and that the real failure was not Ukraine's choice but the thinness of what it received in return.

The lesson other countries learned

The Budapest Memorandum is now cited far beyond Ukraine. It is a staple of arguments in countries debating whether to give up, never acquire, or quietly develop nuclear weapons.

The lesson some governments draw is simple and dangerous: nuclear weapons protect you, and promises do not. Libya gave up its weapons programmes in 2003 and its leader was overthrown with Western military help in 2011, a sequence North Korean officials have pointed to as a reason never to disarm. Ukraine gave up its inherited arsenal and was invaded by one of the countries that had promised to respect its borders. In South Korea and elsewhere, public debate about acquiring nuclear weapons has grown, with Ukraine's experience often mentioned.

The opposite lesson is also available. South Africa dismantled its own small arsenal in the early 1990s and has not been invaded. Kazakhstan and Belarus gave up theirs. Most of the world's countries have never sought the bomb and live in peace. The nonproliferation regime has held far better than its founders feared in the 1960s, when many predicted dozens of nuclear-armed states. A world of many nuclear powers would be far more dangerous for everyone, including Ukrainians.

What the Budapest story really teaches, in this site's view, is that security assurances need to be built to last. If the world wants countries to give up the worst weapons, the commitments they receive in exchange must be specific, credible and backed by more than a single signature. In peace talks since 2025, Ukrainian leaders have repeatedly insisted on binding security guarantees rather than assurances, and Budapest is the reason why.

A pacifist case, and a realist one

Progressives often come to this subject with two instincts that pull against each other. One is a deep commitment to nuclear disarmament; the other is solidarity with a country invaded by a larger neighbour. The Budapest Memorandum tests both.

Here is the argument this site would make. Disarmament is right, and Ukraine's decision in 1994 was a contribution to a safer world that deserves respect rather than mockery. But disarmament only spreads if the countries that take the risk are protected when the bargain is broken. Standing with Ukraine is therefore not a departure from the cause of nonproliferation. It is one of its conditions. A world that let Ukraine's sacrifice go unanswered would be teaching every insecure government the wrong lesson.

That is also a position that has found support across party lines. The Nunn-Lugar programme that paid to dismantle Ukraine's missiles was a Democratic and Republican project, and broad majorities in Congress voted for aid to Ukraine after 2022. Our Pentagon and militarism page follows both the arms debates and the disarmament ones.

What you can do

• Learn the text. The Budapest Memorandum is a single page. Read it, and you will be able to correct both the people who say it obliged the United States to go to war and the people who say it meant nothing.
• Ask Congress how it will judge any peace deal. Use the representatives page to find your representative and senators, with phone numbers, contact forms and their latest votes. Ask what security commitments to Ukraine they believe should accompany any settlement, and whether they would support putting them to a vote.
• Watch the votes on aid and arms control. Our Congress tracker lists bills and recorded votes, including measures on Ukraine aid and nuclear policy.
• Look for the bipartisan record. The common ground page lists bills passed with support from both parties. Nonproliferation has a long bipartisan history worth reminding your representatives about.
• Follow the wider conversation. The human rights and foreign aid page gathers reporting on Ukraine, refugees and security assistance from many sources.