Before voting on accession, Ukraine demanded from Russia, the USA, France and the United Kingdom a written statement that these powers undertook to extend the security guarantees to Ukraine. Instead security assurances to Ukraine (Ukraine published the documents as guarantees given to Ukraine[5]) were given on 5 December 1994 at a formal ceremony in Budapest (known as the Budapest Memorandum on Security Assurances[6]), may be summarized as follows: Russia, the UK and the USA undertake to respect Ukraine's borders in accordance with the principles of the 1975 CSCE Final Act, to abstain from the use or threat of force against Ukraine, to support Ukraine where an attempt is made to place pressure on it by economic coercion, and to bring any incident of aggression by a nuclear power before the UN Security Council.
As it turns out, they might have been better off holding on to a couple of dozen of them instead of relying on security guarantees from the US and the UK.
Given the Ukraine’s horrific history of oppression by outside actors (mainly Russia), that makes me wonder how much pressure was applied to make them sign. “Give up your nukes or you’ll get no gas from us.” (Russia)
Granted, the nukes are also a liability in some ways, and an expense, but in such a dangerous neighborhood...