An excellent response. How about the treaty between NATO and Ukraine? Or the US and Ukraine? There are some treaties between the US and Russia, so "show me the treaty" is always a fine notion.
How about the 1994 Budapest Memorandum, where Russia, the UK, and the US guaranteed Ukraine’s borders in return for Ukraine giving up its nuclear weapons. Russia has violated every commitment it pledged in the memorandum. The US and the UK pledged to support Ukraine in the event of Russian aggression against Ukraine.
Ukraine, the Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and the United States of America,
Welcoming the Accession of Ukraine to the Treaty on the Non-Proliferation of Nuclear Weapons as a non-nuclear-weapon state,
Taking into account the commitment of Ukraine to eliminate all nuclear weapons from its territory within a specified period of time,
Noting the changes in the world-wide security situation, including the end of the Cold War, which have brought about conditions for deep reductions in nuclear forces,
Confirm the following:
1. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America reaffirm their commitment to Ukraine, in accordance with the principles of the CSCE Final Act, to respect the independence and sovereignty and the existing borders of Ukraine.
2. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America reaffirm their obligation to refrain from the threat or use of force against the territorial integrity or political independence of Ukraine, and that none of their weapons will ever be used against Ukraine except in self-defense or otherwise in accordance with the Charter of the United Nations.
3. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America reaffirm their commitment to Ukraine, in accordance with the Principles of the CSCE Final Act, to refrain from economic coercion designed to subordinate to their own interest the exercise by Ukraine of the rights inherent in its sovereignty and thus to secure advantages of any kind.
4. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America reaffirm their commitment to seek immediate United Nations Security Council action to provide assistance to Ukraine, as a non-nuclear-weapon state party to the Treaty on the Non-Proliferation of Nuclear Weapons, if Ukraine should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used.
5. The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America reaffirm, in the case of Ukraine, their commitment not to use nuclear weapons against any non-nuclear-weapon state party to the Treaty on the Non-Proliferation of Nuclear Weapons, except in the case of an attack on themselves, their territories or dependent territories, their armed forces, or their allies, by such a state in association or alliance with a nuclear weapon state.
6. Ukraine, The Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and The United States of America will consult in the event a situation arises which raises a question concerning these commitments.
This Memorandum will become applicable upon signature.
Signed in four copies having equal validity in the Ukrainian, English, and Russian languages.
FOR UKRAINE:
(signature Leonid Kuchma)
FOR THE RUSSIAN FEDERATION:
(signature Boris Yeltsin)
FOR THE UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND:
(signature John Major)
FOR THE UNITED STATES OF AMERICA:
(signature Bill Clinton)
Budapest, 5 December 1994.