The Russian oil oligarchs want the natural gas deposits
They also want don't want a hostile government in Ukraine governing over the gas and oil pipelines that run through Ukraine to the rest of Europe.
The regulars of Slashdot have no difficultly connecting every single policy or action of the US to oil. When Putin and the Russians pull something, however, they get the benefit of the doubt and no rationalization is too outrageous or implausible to be offered.
As for this thread generally; I've seen a few of these "I thought we were better than this now" replies since Putin moved on Crimea. It's frustrating that peace and prosperity produces such naivety. We've accumulated about 60 years worth of la-la land mentality and it's not good for us.
So go on Putin. Start some shit. We need it.