[quote=Aristocles]
I'd say this is a move by an increasingly desperate Putin who thinks that by seizing Crimea, he can distract people from a slowing economy at home at the same time he wishes to rebuild a fraction of "soviet glory." He's also upset that he lost a major ally in Ukraine's ousted president.
[/quote]

It's interesting that you say this. I read a Forbes analysis yesterday which discussed some of the economic repercussions of this incursion, mostly as political retribution by the West, which could threaten the Russian economy more severely than it is now. 

It also examined how crucial the warm water naval port is to Russia's position as a global power. Take away Crimea (where Russia currently leases the naval base in Sevastapof) and you have a military power without timely sea access to Europe, Asia Minor and North Africa. The Russian fleet wouldn't be much of a threat if you could spot it coming your way all the way from Gibraltar.