The fact is that we are effectively helpless because our military is stretched past the breaking point. Unless we engaged in a serious pull out from Iraq, a logistics nightmare that I am far from confident our contractor-run military could handle at this point, we could not mount a credible land or naval offensive in support of Georgia. Fatlefty can correct me if I am wrong, but I think the best we could muster is an aircraft carrier, support fleet and subs in the Mediterranean and Black sea. Most of the naval assets are reallocated to the Persian Gulf.
That sends significant messages to Ukraine, Iran, Syria, Israel, and other powers in the region or in the ripple effect. The message to U.S. allies is "You're on your own." The message to non-allies, particularly Iran and Syria, is "Russia is a power that can offset U.S. military force." Until now, conventional wisdom was that the Russian military had collapsed with the Soviet Union and was basically reduced to raping helpless Chechens. The invasion of Georgia shows that Putin has done a credible job rebuilding the Red Army -- sufficient to menace Ukraine and sufficient to support Iran or Syria in the event of a proxy conflict with Turkey or Israel.
Turkey, Azerbaijan, and Israel, in turn, now know they need to keep the Russians on good terms. Israel can count to some degree on distance and traditional mechanisms of survival (Israel has always believed it would need to go it alone someday -- having a persecution complex is sometimes functional). But Turkey in particular will need to undergo serious reevaluation, particular since Europe has dicked around on its EU application. If Turkey is actively courted by Russia as a potential anti-EU/anti-U.S. counterweight, that will be bad news for us.