[WinstonSmith84]

Yes they did (with Russia)

https://en.wikipedia.org/wiki/Ukraine_and_weapons_of_mass_de...

> ... In 1994, Ukraine agreed to transfer these weapons to Russia ... in exchange for economic compensation and assurances from Russia, the United States and United Kingdom to respect the Ukrainian independence and sovereignty in the existing borders....

And yes there is this point but this is irrelevant. Ukraine played by the rules and got played. Nobody would have invaded Ukraine in 1994 if they had refused, especially given the state of the Russian army at this time

> While all these weapons were located on Ukrainian territory, they were not under Ukraine's control.[4]

[arandomusername]

> Seek immediate Security Council action to provide assistance to the signatory if they "should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used".

Which they did. Please tell me which exact aspect of the Budapest Memorandum did US not follow through?