Two promises, neither a guarantee
Published 6 October 2026
The Budapest Memorandum was signed on Monday, 5 December 1994, by Ukraine, Russia, the United Kingdom and the United States, alongside Ukraine's accession to the Nuclear Non-Proliferation Treaty as a non-nuclear state and its commitment to eliminate nuclear weapons from its territory. The UN Treaty Series records the document as a memorandum on security assurances, with entry into force by signature. (UN Treaty Series, volume 3007, I-52241)
The first three assurances were explicit. Russia, Britain and the United States reaffirmed respect for Ukraine's independence, sovereignty and existing borders; undertook to refrain from the threat or use of force against its territorial integrity or political independence except in self-defence or otherwise under the UN Charter; and reaffirmed that they would not use economic coercion to subordinate Ukraine's sovereign rights to their own interests. These are commitments about the conduct of the signatories themselves. (Budapest Memorandum, paragraphs 1-3, UN Treaty Series)
The memorandum's fourth assurance concerned seeking immediate UN Security Council action to assist Ukraine if it faced aggression or a threat of aggression involving nuclear weapons. The fifth concerned non-use of nuclear weapons against a non-nuclear NPT state, with the specified exception for attacks associated with a nuclear-armed state. Its sixth paragraph provided for consultation when questions arose about these commitments. That architecture matters: a consultation clause and an undertaking to seek Security Council assistance are not the same as NATO's collective-defence framework. (Budapest Memorandum, paragraphs 4-6,5 December 1994)
NATO's Bucharest declaration supplied a later, different promise. Issued on 3 April 2008, it said Ukraine and Georgia "will become members of NATO" and described a Membership Action Plan as the next step on their direct path to membership. It supported their applications for that plan and said foreign ministers would assess progress at their December 2008 meeting, with authority to decide on the applications. The declaration thus combined an eventual-membership statement with an unfinished admission process. It did not announce that Ukraine had joined the alliance, set an accession date or extend membership's defence obligations to it that day. This distinction prevents the promise of a future destination from being rewritten as an immediate treaty protection. (NATO, Bucharest Summit Declaration, 3 April 2008, paragraph 23)
The same declaration treated NATO-Russia cooperation as a continuing instrument. It said the NATO-Russia partnership was a strategic element in fostering security in the Euro-Atlantic area and called for a more constructive relationship. That contemporaneous framing belongs beside the Ukraine membership language, rather than being omitted to make 2008 look like a single-purpose announcement aimed only at Moscow. A summit document can contain both a membership aspiration Russia opposed and an attempt to sustain cooperation with Russia. (NATO, Bucharest Summit Declaration, 3 April 2008, Ukraine/Georgia and NATO-Russia sections)
The Budapest text is specific about what its signatories undertook, and careful about what it did not promise. Signed on 5 December 1994 by Ukraine, Russia, the United States and the United Kingdom, the memorandum accompanied Ukraine's accession to the Nuclear Non-Proliferation Treaty as a non-nuclear-weapon state. Russia, Britain and the United States reaffirmed respect for Ukraine's independence, sovereignty and existing borders; undertook to refrain from threats or use of force against its territorial integrity or political independence; and undertook not to use economic coercion to subordinate Ukraine's sovereign rights. They also committed to seek immediate UN Security Council action to assist Ukraine if it became the victim of aggression or a threat of aggression involving nuclear weapons. The separate nuclear-use assurance had exceptions for an attack on a signatory, its territory, forces or allies by a non-nuclear state acting in association with a nuclear-weapon state. All four signatories agreed to consult if a situation raised a question about these commitments. The memorandum's text contains no automatic mutual-defence clause. (UN Treaty Collection, UN Security Council record)
The assurances came at the end of a denuclearization sequence, not as an operational NATO guarantee. Ukraine's 16 November 1994 accession law made deposit of its NPT instrument conditional on security guarantees being formalized in an international document. On 5 December, it acceded as a non-nuclear-weapon state and the memorandum was signed. In June 1996, Ukraine and the White House announced completion of the transfer of its last strategic nuclear warheads to Russia; a U.S. archival fact sheet distinguished those warheads from about 2,500 tactical weapons transferred in 1991-92. The 1996 announcement described the remaining strategic warheads, not the later elimination of delivery vehicles, which continued after that date. (Ukrainian parliament)
Bucharest added an explicit NATO membership destination but left the next step unresolved at the summit. On 3 April 2008, NATO leaders said Ukraine and Georgia "will become members," endorsed MAP as the next step, and asked foreign ministers to assess progress in December, with authority to decide on applications. The declaration did not say they were already members or set an accession date. U.S. Secretary of State Condoleezza Rice described the MAP debate before the December meeting as one about how to implement Bucharest, not a change to the stated future-membership position. On 3 December, NATO's foreign ministers reaffirmed the Bucharest decision but chose annual national programmes and assistance through NATO-Ukraine and NATO-Georgia commissions "without prejudice to further decisions" on MAP. Thus "will become members" was the declared political destination; MAP remained undecided and no entry timetable was supplied. (US State Department, NATO ministers)
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