Killing one person is murder, killing 100,000 is foreign policy
Sorry, but I don't believe we should be the World Police. I don't believe this is a problem for the U.S. This isn't Nazi Germany in the 30's, this isn't Eastern Europe during the Cold War. Is it provocative and disturbing? Yes. Nobody likes it. Everybody is pissed at Putin. But this isn't worth risking a full scale war in Europe over. Hell the Crimean citizenship doesn't want to be part of the Ukraine anyway. They were already trying to secede and position themselves closer to Russia before this happened. It's not like they are needing "liberated."
The last time the U.S. tried to export "freedom and democracy" we leveled two nations into ruin and killed tens of thousands of people in the process.