The Budapest Memorandum
Budapest Memorandum on Security Assurances is an international treaty signed on 5 December 1994 in the Hungarian capital Budapest by Ukraine, the United States of America, Russia, and the United Kingdom concerning the nuclear disarmament of Ukraine and its security relationship with the signatory countries.
According to the memorandum, Russia, the USA, and the UK confirmed, in recognition of Ukraine becoming party to the Treaty on the Non-Proliferation of Nuclear Weapons and in effect abandoning its nuclear arsenal to Russia, that they would:
Respect Ukrainian independence and sovereignty within its existing borders.
Refrain from the threat or use of force against Ukraine.
Refrain from using economic pressure on Ukraine in order to influence its politics.
Seek United Nations Security Council action if nuclear weapons are used against Ukraine.
Refrain from the use of nuclear arms against Ukraine.
Consult with one another if questions arise regarding these commitments. - See more at: http://www.deltanewsandreview.com/2014/03/usa-uk-must-honor-ukraine-treaty.html#sthash.5ZVj2P34.dpuf