After the Soviet Union and the Eastern Bloc disbanded a problem became apparent. The security of nuclear weapons of the Eastern Bloc nations could not be guaranteed. To avoid the problem of nuclear proliferation the Budapest Memorandum was written. It promised Belarus, Kazakhstan and Ukraine security if they handed nuclear weapons on their soil to the Russian Federation. It was signed on December 5 1994.

The four memoranda were originally signed by four nuclear powers: Ukraine, Russia, the United States, and the United Kingdom. France and China gave individual assurances in separate documents. Ukraine sent it’s nuclear weapons to Russia as promised.

Three things agreed to, among others, are as follows

• Respect the signatory’s independence and sovereignty in the existing borders (in accordance with the principles of the CSCE Final Act)
• Refrain from the threat or use of force against the territorial integrity or political independence of the signatories to the memorandum, and undertake that none of their weapons will ever be used against these countries, except in cases of self-defense or otherwise in accordance with the Charter of the United Nations.
• Refrain from economic coercion designed to subordinate to their own interest the exercise by Ukraine, the Republic of Belarus, and Kazakhstan of the rights inherent in its sovereignty and thus to secure advantages of any kind

Russia violated the Budapest memorandum in 2014 with its annexation of Ukraine’s Crimea. As a response, the United States, United Kingdom, and France provided Ukraine with financial and military assistance, and imposed economic sanctions on Russia, while ruling out “any direct interventions to avoid a direct confrontation with Russia” Wikipedia

China supplying weapons to Russia for use in Ukraine could also be considered a violation of the Budapest Memorandum.

US President for Life hopeful Donald Trump signing away Ukraine land for a deal with his buddy Russian President for Life Vladimir Putin is also a violation of the terms of the Budapest Memoranda.

• Why Ukraine gave up its nuclear weapons — and what that means in an invasion by Russia (soon to be defunded) NPR
• China Powers Russian Drone Warfare: Ukraine Discovers Fully Chinese-Made UAV Used as Decoy Defense Security Asia