So I realize I am playing devil's advocate here, and I feel akin to a writer speculating on the motives of Hitler after the Sudetenland, but just for the sake of argument: is the absorption of Crimea into Russian really as horrible as all that? I mean, let's be clear on a few points here. 1) I don't mean to sound like a pre-WWI irredentist here, but the reality is that Crimea is mostly ethnic Russian, and Russian is the predominant language. 2) By my count, Crimea's history is one of constant change of ownership....they seem to change hands roughly every 150 years over the past few millennia. 3) The population of Crimea seems to have genuinely wanted this transfer to Russia. 4) The Ukrainians' lack of ability to maintain a stable central government for the past decade, sort of argues in favor of disaffected minority regions splitting off: if you can't get your act together in Kiev, don't be surprised when people look for other solutions.
Arguments against: Well, really just one, and that's Putin himself. After South Ossetia and now Crimea, what are the limits of his ambitions for 'Greater Russia'? If gays are his Jews and Crimea is his Sudetenland (or arguably his Anschluß), then what can we expect next? We look back with perfect hindsight to the 1930s and see it all as inevitable and we judge the leaders of the time accordingly; but the fact is that they were dealing with incomplete information, just as we are now. Where is Putin going with all this? That's the million-dollar question. Or potentially the million-life one.