Not the same situation. Soviet nukes were soviet, with good chunks of them buit in Ukraine.
See for instance where that was built: https://en.m.wikipedia.org/wiki/R-36_(missile)
Also, Chernobyl.
See for instance where that was built: https://en.m.wikipedia.org/wiki/R-36_(missile)
Also, Chernobyl.
The answer is probably because the alternative was too scary for the west. Better to keep dealing just with Moscow.