The Budapest Memorandum, signed in December 1994, resulted in Ukraine voluntarily handing over its nuclear arsenal, as well as other military stocks and munitions, to Russia.
In exchange, Moscow vowed to respect Ukraine's sovereignty, security, and territorial integrity.
The U.S. and the U.K. were among the co-signatories, but stopped short of providing "guarantees" (which would have entailed a direct military intervention) and instead offered "assurances," a term that left some wiggle room for a response to potential aggression from Moscow.
