[GawainBS]

I think the main reason for the Russian involvement is the oil and gas. Like Gaelraen said, the "coming to the aid of citizens" is a ploy and an excuse. You have to tell your citizen a reason why their sons & daughters are going to die. The tricky part, however, is that Georgia is in the queue for a NATO membership. I doubt that in the current situation any other nation would interfere, though, since a) it's basicly an internal matter and b) frankly, the only nation with sufficient military strength to do so (USA), is overstretched at the moment. Further, the Russions wouldn't tolerate this.
The UN is out of the game, by default. The only option that remains, is a joint EU force, but since all the posters in this thread are Europeans, I don't have to point out how decisive the EU is.