Stratfor has a very persuasive analysis of the entire situation in Georgia, in particular how it is not the beginning of a new balance of power but rather the manifestation of an already-changed one. It shows that the predictable US response is likely to do little to help Georgia, while hurting US credibility:
By invading Georgia as Russia did (competently if not brilliantly), Putin re-established the credibility of the Russian army. But far more importantly, by doing this Putin revealed an open secret: While the United States is tied down in the Middle East, American guarantees have no value. This lesson is not for American consumption. It is something that, from the Russian point of view, the Ukrainians, the Balts and the Central Asians need to digest. Indeed, it is a lesson Putin wants to transmit to Poland and the Czech Republic as well. The United States wants to place ballistic missile defense installations in those countries, and the Russians want them to understand that allowing this to happen increases their risk, not their security.
The Russians knew the United States would denounce their attack. This actually plays into Russian hands. The more vocal senior leaders are, the greater the contrast with their inaction, and the Russians wanted to drive home the idea that American guarantees are empty talk.