It would be interesting as to how this would affect nuclear proliferation around the world. I wonder if aspiring nuclear powers like Iran, or nations with less advanced nuclear stockpiles, would be able to purchase some old soviet nukes from impoverished ex-Soviet states...
Of course, I suppose that if such was possible, the West and Russia would get really angry really quickly.
Non-proliferation was the primary reason for the US encouraged/supported Ukraine and others getting rid of their nukes. Also, if Russian owns those nukes, then they're counted in START discussions. If, instead, Ukraine owns them but became a Russian puppet state, then Russia would argue those nukes don't count.
That being the case, in 1994 Russia, US, UK made commitments to Ukraine if they signed the Non-Proliferation Treaty and got rid of their nukes. Those included:
- Respect the independence and sovereignty and the existing borders of Ukraine
- Refrain from the threat or use of force against the territorial integrity or political independence of Ukraine
- 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.
- Assist Ukraine (as a non-nuclear-weapon country) if Ukraine should become a victim of an act of aggression or an object of a threat of aggression in which nuclear weapons are used.
It seems pretty clear that Russia violated a couple of those and that the US and UK were not willing/able to do anything about it.