In 1994, Ukraine joined the NPT as a non-nuclear weapons state, a decision that entailed relinquishing world’s third largest nuclear arsenal. This constructive move came at a price: the United States, Russia, and the United Kingdom pledged to Ukraine security assurances in a Memorandum on Security Assurances, signed in Budapest on December 5, 1994. The Budapest Memorandum, as the document became known, aimed at addressing precisely what happened in Crimea in 2014. The breach of the Memorandum by one of its signatories has been damaging enough. The removal of the sanctions for this breach by other signatories would render it utterly worthless and deal a devastating blow to the international nonproliferation regime, of which the Memorandum has become a constitutive part.