Which is the reason why they started the war in the first place. They feel cornered. And a smarter politics by the west, would not have pushed them so much.
But I am all for self determination of even the smallest states.
But I do not really see this as the goal or applied politics of the US, nor EU, nor obviously russia.
It can happen as a side product, like when the kurds were supported, when it fit the greater game and dropped when that changed. And now Ukraine is important and get supported and tomorrow that can change again. The determining factors are likely not idealism.