You guys know military action isn't the only option, right? If Obama has any actual clout in the world and the guys to do it, he should get the rest of the Western world to immediately halt all trade with Russia until they withdraw all troops from Ukraine. That would actually be a gigantic consequence for Russia that would likely force Putin to back off.
But my bet is that Obama has so little cache or desire to actually pull that off.
We could be a lot more than hot air without committing a single troop.
Russia has a major military base inside Ukraine, and to secure that base and their interests with an unstable government is something we would do ourselves in the same situation. HOW THEY DO IT is a different matter and this is obviously in no small part, a show of force in a region that is more than half ethnically Russian.
Crimea has been disputed for decades, even during the Soviet Union. It was an autonomous region even in Soviet times, and pretty much the Sicily of Eastern Europe...everyone has had her. It is ethnically diverse, and the people there can't figure out side they want to be on. It is much like Transnistra in Moldova, belonging to one country but having a majority of the population dedicated to the other. The Ukraine is the place in Europe where battles are fought and it has changed hands a lot during the centuries, that makes it a melting pot and melting pots never have worked well in Europe (the Former Yugoslavia as the best example).
Ukraine is in a bad spot, always have been. They can't completely commit to the west because of the ethnic Russian influence, but more so because they are economically unable to make such a move without a complete bailout by the west. That's not going to happen in a country that pulls from within depending on which way the wind blows. They depend on Russia for energy, because it's too damn expensive to get from Europe and because of recent history.
They were never fully committed to democracy, and never fully committed from moving away from their historic regional partner in Russia. What did Lithuania, Estonia and Latvia do as soon as they could? They got away from Russia, they wanted nothing to do with it (maybe Latvia for a time). Ukraine and Belarus and to a lesser extent Moldova, never have strayed too far. It's for reasons beyond ethnic makeup, it has to do with national security and the specter of an angry Russia. Belarus has quietly created a police state, not really all that different from what they were during the Soviet Union. They treat dissidents like Uzbekistan does, they crush them.
The Ukraine on the other hand has a lot of free thinkers and connections to the west, so they feel a connection to Europe is wise for their future. That may be true but the fact that they are so dependent on Russia for not only energy, but for internal strength and national security. Theoretically they can straddle Europe and Russia for decades upon decades, but there will always exist things from the core that will make it unstable. It is not for the U.S. or Europe or even Russia to save, it has to be something they work out by themselves. To that end the Russians will influence what they can, and a European response will do the same.
Rushing to judgment about cutting off trade ties with Russia or massing troops or whatever is reactionary. Europe needs to stand with us in a calculated and measured way and then we have to see what the Russians are willing to negotiate. The bottom line is Russia has a vested interest in the Ukraine, we don't. For Europe the interest is along borders as Romania, Poland, Slovakia and Hungary all share borders with the Ukraine and the Black Sea has a ton of Western commerce. Russia is not invading the Ukraine and sacking Kiev, people need to see it for what it is and expect a lot more of this to happen in former Soviet Republics and elsewhere over the next 50 or so years.