I don't see a thing Obama could do and not shoot himself in the foot? Military is not an option. Diversifying energy sources is unrealistic. Diplomatic jibber jabber do nothing. Favourable for the States scenario of Ukraine going the route of Yugoslavia doesn't look good either.
Here's what will happen. Planned presedential elections in May either won't happen or will only heat up the confrontation, which in turn will lead to the backtrack of the events to the February (even Yanukovich might be back, this is not out of the question). By this year's end there will be new presedential elections with the set of old (aside from pro-Nazi and nationalists parties) and new candidates, whoever wins will declare normalization of the situation in Ukraine with actions to follow. Actual legal status of Southern and Eastern parts of Ukraine is irrelevant (federalization or not), but Ukraine de-facto will be in one piece (minus Crimea). This effectively will end Ukrainian crisis, or at least political crisis, economy holes won't go away that easily.
