Maybe learn your history before you post?
Ukraine gave up their nuclear weapons, because Russia, US, UK and France would make sure they regained their sovereignty. That was the original deal, first Russia invaded Crimea and we did nothing and now US won't even back the invasion and war in Ukraine.
en.m.wikipedia.org
The memoranda, signed in Patria Hall at the Budapest Convention Center with U.S. Ambassador Donald M. Blinken amongst others in attendance,[3] prohibited Russia, the United States, the United Kingdom and France from threatening or using military force or economic coercion against Ukraine, Belarus, and Kazakhstan, "except in self-defence or otherwise in accordance with the Charter of the United Nations." As a result of other agreements and the memorandum, between 1993 and 1996, Belarus, Kazakhstan and Ukraine gave up their nuclear weapons.[4][5]
Russia breached the Budapest memorandum in 2014 with its annexation of Ukraine's Crimea.[6][7] As a response, the US, UK 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".