A little bit of history: Solzhenitsyn was part Ukranian but even he felt Donbas and Crimea should be Russia's, and that it was dangerous for western Ukranian leadership to foment hatred towards Russia. It would help put both countries on a path to war. How right he was.
If we find ourselves supporting a war to take back Crimea (which Obama effectively ceded) and Donbas, then all bets are off.
Solzhenitsyn quote:
Maybe it will be necessary to have a referendum in each region and then ensure preferential and delicate treatment of those who would want to leave. Not the whole of Ukraine in its current formal Soviet borders is indeed Ukraine.
Some regions on the left bank [of the river Dnepr] clearly lean more towards Russia. As for Crimea, Khrushchev's decision to hand it over to Ukraine was totally arbitrary. And what about Carpathian (Red) Ruthenia? That will serve as a test too: While demanding justice for themselves, how just will the Ukrainians be to Carpathian Russians?