Holy shit this is updated quickly.
Anyway Georgian army retreated, all of their tanks are destroyed and the city of Tskhinvali is secured by Ossetian and Russian armed forces. This would seem to end shortly after it started, but the Russian president said that he will "punish the aggressors" which I would interpret as "fuck the Georgian president in the ass".
Actually, there's several things that the US could do. Just nothing involving troops on the ground, we could still tomahawk the ever living fuck out of 'em.
You should know the game, when US/Russia goes to war, then the other one can't get involved directly. US goes to war in Vietnam, Russia supplies NVA with equipment, Russia goes to war in Afghanistan, US gives supplies and training. When that rule of the game is broken, then we have WW3 and god help us all.
And the EU is, as Ace said, not a military alliance. If the EU was attacked by someone they'd have to rely completely on NATO forces to protect them. And most NATO forces are, amazingly enough, American.
Tsk tsk, UK and France have nukes, the EU will not be attacked.