So Ukraine says "hey, we think we probably want to join NATO". And NATO responds "cool, that sounds good", and... so what? Ukraine is a sovereign nation and should be allowed to ally itself with whatever country or group it wants to. Perhaps Russia should take a hard look at why Ukraine didn't feel that allying with Russia would be in their best interests?
So, Mexico is a sovereign nation and should be allowed to ally with North Korea or Iran, right?
The USA would be understanding of Mexico’s sovereignty and stand by while North Korea sends military aid to Mexico, installs their elite sons and daughters as board members of Mexico’s largest corporations, and blatantly strategizes who will become the “elected” leader of Mexico.
Perhaps you should take a hard look at the reality of what all powerful nations do when they feel threatened by their foes close to their borders. Ignoring it is at everyone’s peril.