No, I'm with Santiago here that the US probably has the ultimate upper hand militarily, but at atrocious cost and Russia really wants neither a failed state nor a smoking crater in the heart of the old Rus.

The failed state risk is an important perspective in my opinion. The US doesn't have a problem with failed states as buffer states, especially far away from the US mainland. And clearly the trigger for Russian action in Crimea has been a collapse of state power in Ukraine including things like a (short-lived, but that just adds to the perception that Ukraine does not have a functioning state) repeal of legal protections for minorities.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman