Chivers has a good article on what the Wikileaks cables reveal about the run up to the South Ossetia War:
The cables show that for several years, as Georgia entered an escalating contest with the Kremlin for the future of Abkhazia and South Ossetia, two breakaway enclaves out of Georgian control that received Russian support, Washington relied heavily on the Saakashvili government’s accounts of its own behavior. In neighboring countries, American diplomats often maintained their professional distance, and privately detailed their misgivings of their host governments. In Georgia, diplomats appeared to set aside skepticism and embrace Georgian versions of important and disputed events.
By 2008, as the region slipped toward war, sources outside the Georgian government were played down or not included in important cables. Official Georgian versions of events were passed to Washington largely unchallenged.
The last cables before the eruption of the brief Russian-Georgian war showed an embassy relaying statements that would with time be proved wrong.
The Georgians had the most information, and a strong incentive to present intelligence in the best possible light to the United States. The US, it appears, had neither the interest nor the capability to evaluate Georgian claims. Thus far, however, there doesn’t seem to be anything explicit or implicit in terms of a commitment of support from Washington.