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 Final Act of the Conference on Security and Cooperation in Europe, 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;
A decent argument can be made that the West's monkeying around with Ukraine's government (insofar as corrupt influence-peddling goes, especially vis-a-vis America going back to 2013-2014) constituted a violation of Item #3, after which all bets were off.
But this Memorandum is a red herring anyway, because it lacks any means of compliance or enforcement that would be binding upon those who violated the terms therein.
This is the great fiction of "international law": it only has teeth so long as the nations who are the Great Powers agree to abide by them. Once a Great Power (be it America, China, Russia, etc. going back to the empires of old, including the British Empire, the French Empire, the Spanish Empire, and so on) decides that violating an agreement or a 'treaty' (because this memo, lacking ratification by Congress, can hardly be called a treaty) is within their national interest, they will do so (regardless of who else in the world complains).
That is the lesson of history.
But this Memorandum is a red herring anyway, because it lacks any means of compliance or enforcement that would be binding upon those who violated the terms therein.
***So then the Ukes are free to pursue the nuke option, which they said explicitly. Since they had the 3rd largest nuke arsenal before they dismantled it, we can safely assume that there’s some Ukes who know how to build Nukes.
The nukes will provide the “means of compliance or enforcement”.
If I were Ukranian, I’d be busy doing pretty much exactly that.