The Budapest Memorandum on Security Assurances, signed on 5 December 1994, stands as a pivotal moment in post-Cold War geopolitics. Emerging from the ashes of the Soviet Union, it marked a rare convergence of nuclear disarmament and multilateral diplomacy. Ukraine, Belarus, and Kazakhstan, each inheriting a share of the USSR’s vast nuclear arsenal, were persuaded to relinquish their strategic weapons in exchange for assurances from the United States, the United Kingdom, and the Russian Federation. The signing took place at an OSCE summit in the Hungarian capital, hence the document’s name.

At the heart of the memorandum was Ukraine’s possession of the third-largest nuclear arsenal in the world. Though the warheads were technically under Russian operational control, they remained physically on Ukrainian soil. The U.S. in particular led efforts to prevent the emergence of new nuclear states from the former Soviet republics, promoting the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) as the legal mechanism for disarmament. In return for joining the NPT as a non-nuclear weapon state, Ukraine was promised political assurances regarding its sovereignty, territorial integrity, and security.

The terms of the Budapest Memorandum were significant, though pointedly not binding under international law. The signatories pledged to respect the independence and existing borders of Ukraine, refrain from the threat or use of force, and avoid economic coercion. They also committed to seek UN Security Council action if nuclear weapons were ever used against Ukraine, and promised not to use nuclear weapons against the country themselves. The inclusion of a clause requiring consultations in the event of disputes or threats was intended to provide a diplomatic channel in times of crisis.

What is critical to understand is that the memorandum was not a formal treaty. It lacked enforcement mechanisms and legal penalties, relying instead on political goodwill and international norms. This distinction would prove fatal to its credibility two decades later.

The annexation of Crimea by the Russian Federation in early 2014, followed by its support for separatists in the Donbas region, represented a direct challenge to the core principles enshrined in the Budapest Memorandum. Ukraine’s territorial integrity was violated by a state that had explicitly committed to uphold it. While the United States and the United Kingdom issued strong condemnations and imposed sanctions on Russia, neither country provided direct military support to Ukraine, citing the memorandum’s non-binding nature.

Russia, for its part, has argued that the circumstances of 2014, namely, the change in Ukraine’s government following the Maidan Revolution, nullified the commitments under the agreement. It has also claimed that Crimea’s “referendum” justifies its actions. These positions are widely rejected by the international legal community and by the other signatories of the memorandum, but the damage to the credibility of security assurances was done.

The legacy of the Budapest Memorandum is now viewed with a mix of regret and realism. It illustrates the limits of non-binding agreements in deterring aggression by great powers, and it has become a central reference point in discussions on nuclear disarmament and non-proliferation. For Ukraine, the memorandum is a bitter reminder of the price paid for denuclearization without robust, enforceable guarantees. For the global community, it raises hard questions about the viability of relying on political promises in an increasingly unstable world.

The Budapest case has also had ramifications beyond Eastern Europe. It has been cited by countries such as North Korea and Iran in debates over nuclear policy, reinforcing the perception that possession of nuclear weapons may offer more reliable security than any assurance signed on paper. In the decades since, the gap between rhetoric and reality in international security agreements has only widened.

Sources
• United States Department of State Archive. Background Briefing on Ukraine, March 2014. https://2009-2017.state.gov
• United Nations Office for Disarmament Affairs. Treaty on the Non-Proliferation of Nuclear Weapons. https://disarmament.un.org
• Council on Foreign Relations. Why Ukraine Gave Up Its Nuclear Weapons, 2022. https://www.cfr.org/backgrounder/why-ukraine-gave-nuclear-weapons
• Chatham House. Ukraine, Russia and the West: The Budapest Memorandum at 30, 2023. https://www.chathamhouse.org