If you let Russia control Europe, then they are the global superpower, not us. You want to live in a Russian world?
But your small-minded outlook is playing checkers while the Russians are playing chess.
And yes, when you're in a negotiation you need to be holding some cards. Otherwise you're just begging. Obama is a spineless wimp, he clearly won't do anything in response to Russia's aggression, so they remain in Crimea and make themselves right at home. If we're not careful, they will take the rest of Ukraine as well.
The only reason they haven't yet is because the Ukrainians, not the Americans, would fight back. What's Obama gonna do in that case?