15 years ago, Croatia and Bosnia-Herzegovina both, at separate times, both left Yugoslavia. The United States sent forces over to help these fledgling nations in their quest for independence. In 1998, the United States, against the expressed desire of the United Nations and, with our President violating the War Powers Resolution and NATO Charter, invaded Yugoslavia to defend the Kosovar Albanians who wanted to be separate, but still a part, of Yugoslavia. In 2003, we invaded Iraq, contrary to the desire of the United Nations and with, what turned out to be (and may have been known to those making the decisions) erroneous information, with, at least a long-term goal of securing a Status of Forces Agreement allowing us to keep our forces in the nation/region for long-term - oh yeah, and to free them.
Recently, Russian troops invaded Georgia after the Georgian military attacked South Ossetia, a state that was attempting to assert independence from Georgia. The Russian attack has been derided by John McCain and the Bush Administration and the Conservative talk circuit as attempting to re-create the Cold War, attempting to rebuild the Russian/Soviet empire.
What's the difference? Someone else's sphere of influence. This isn't us invading or attacking; it's someone else, and that means empire building. We free nations; look at Iraq! They have their own government (who some on the Right have been attacking for daring to suggest that a long-term security agreement is not what they might want as a free and independent nation), set up by our nation and supported by our military - you know, the one that would stand down as the Iraqi army stood up. Notice you don't really hear about that anymore... but they're free. Other nations are creating puppet regimes friendly to their ambitions, or just outright conquer the nation, at least, that's what the spin is.
I don't jump to vilify Russia on this matter simply because I view this approach as highly hypocritical given our nation's international endeavors over the past 15 years.