Cuba was more of a sovereignty/sphere-of-influence problem than a nuclear-warfare problem. That ship has long since sailed with regard to Russia's borders. Moscow is half-surrounded on the west, as well it should be given its history of combining expansionist behavior with atrocities like communism and the Holodomor.

The Russians have had more than ample opportunity to join the civilized world and stop acting like dicks, but that's apparently not what they want to do. So, containment it is.

And if they feared NATO encroachment on their borders, trying to take over Ukraine was a really stupid way to discourage that. Nukes are scary enough, but nukes in the hands of stupid people are downright terrifying. Personally I doubt any of theirs still work, but that's all too easy to say.