Russia overrunning Georgian positions and seizing land accomplishes nothing for Russia, because unless they occupy, they just have to give it back.
On the other hand, if you arm citizens and trigger a bloody guerrilla war, you can have a nasty ethnic fight and wash your hands of the whole affair at the same time. Once you turn two peoples against one another, you'll have a devil of a time putting the genie back in the bottle. That's what the Russians are counting on. Russian military force cannot achieve separation, in this instance. Only a bloody civil war can do that.
So, Russia renounces force, and the Georgian military does as well, and what's left? Guerrillas.
Which makes me wonder what those who are now calling for respect for Georgian territorial integrity, despite the desires of the South Ossetians, thought of the war in Chechnia. Is it a set of values which guides us, or do we simply decide what to condone and condemn based upon which side the Kremlin happens to be on?
So, Russia renounces force, and the Georgian military does as well, and what's left?
Or Georgia could do what it did today and begin attacks less than 24 hours after agreeing to cease the use of force... "Pretending that you already know the answer when you don't is not actually very helpful." ~Migeru.
Renouncing violence from both parties does not mean that violence ends or that tensions cease.
As in Kosovo, you always have other actors in the field ready to rile things up.
Russia doesn't gain from a full-fledged war. They gain much more by supporting rebels.
Russia will continue to foster rebels throughout the ex-Soviet states but will at times feel it necessary to demonstrate their might. Ukraine has no doubt got the message today.