I don't think we've being paying enough attention to this situation. I certainly haven't been hearing much about it.
It seems that Ukraine is in the midst of a civil war in slow motion between the Moscow oriented horsemen-turned-coalminers on the east bank of the Dnieper, led by Yanukovych and the Western oriented farmers-turned-capitalists on the west bank. The Orange Revolution / Civil War continues. (Or is it the Kulak War continues?)
Moscow has an emotional stake in this game. Moscow's origins are as a Rus trading post among the Eastern Tribes at the edges of the Rus trading empire (kind of like York Factory). The Rus are tightly connected to Sweden, Finland and Estonia - which share a common predilection with Ukraine for Blue and Gold as national colours. Moscow's ruling elements always considered themselves Rus, and have come to dominate the territory they call Russia.
But like many rulers in an effort to survive amongst their subjects they have essentially gone native. They no longer share the same culture or value system as the people they claim to be.
The Dniepr represents the dividing line between the Rus heartland on the West Bank and the Steppes on the east bank. For the Moscovites to lose the West Bank would leave them isolated from their "family" and adrift amongst people they don't really see as equals.
Short form, Moscow will fight for Kiev. They may not be willing to put tanks on the street yet but they might if invited in after things turn violent.