The best course of action for the United States regarding the Georgia-Russian War is to stay out of it. The relationship between those two nations is going to have to worked out eventually. There has been problems going back to the czars and further. Any artificial conclusion mandated by the UN or the US will only postpone the inevitable. It is clear that nations will wage war over century old, even millenium old, disputes.
It is none of our business and we should listen to the founders and avoid foreign entanglements. We must quit NATO, the UN and end all of our trade agreements. We can behave appropriately towards foreign nations without giving up our national sovereignty.