Perhaps the objective isn't to conquer the whole of the Ukraine, but only most of it, leaving the western parts independent.
This seems to be pushed as the right approach wrt the Ukraine in Alexander Dugin's Foundations of Geopolitics, which apparently is used as the source for Russia's current "Eurasianist" geopolitical doctrine:
Perhaps the objective isn't to conquer the whole of the Ukraine, but only most of it, leaving the western parts independent.
This seems to be pushed as the right approach wrt the Ukraine in Alexander Dugin's Foundations of Geopolitics, which apparently is used as the source for Russia's current "Eurasianist" geopolitical doctrine:
https://en.wikipedia.org/wiki/Foundations_of_Geopolitics