In this video, Ron Paul notes what is obvious to any actual libertarian: US intervention in Ukraine is a horrible idea. But at 2:45 he also notes that it would probably be prudent for the Ukrainians to pursue a policy of “separation” into smaller units of government. In this case, of course, the logical thing do would be to decentralize into one at least pro-Western country and at least one pro-Russian country. Or, as Paul notes here, another option is to create a “confederation” with two or more autonomous areas of Ukraine that can govern themselves internally in each region while still formally part of Ukraine.
Either way, decentralization and confederation is always preferable to civil war.