Budapest Memorandum (1994)
Ukraine gave up the world's third-largest nuclear arsenal in exchange for assurances from Russia, the United States and Britain that its borders and sovereignty would be respected.
The memorandum was not a binding defense treaty and was never submitted for ratification as one.
Russia's 2014 annexation of Crimea and 2022 invasion exposed the limits of the assurances, shaping Kyiv's demand for enforceable guarantees today.
Ukraine's insistence on credible guarantees, rather than another round of political assurances, comes directly from this experience.
