re: “if anyone has the horsepower available for a land war in their own backyard, its Russia”
Just like so many other things in life, it depends. Just on the other side of the Caucasus mountains from South Ossetia is the Chechen Republic, which has been at war intermittently with Russia from approx. 1995 to approx. 2003. Large parts of Chechnya still experience low level conflict with Russia. More clearly: very close to Georgia, and on the same side of the Caucaus mountains as the Russian supply lines, there are still a large number of experienced, violent, and not completely passified Chechens who probably would be more than happy to tie down Russian forces in this conflict. Chechens have been reproducing like crazy in the last few decades, and there’s therefore a large pool of young people to be led by their more experienced relatives against the Russians, should Chechens decide they want to “get some.”
On the other side of Georgia, there’s Turkey, which has historically had a great interest in not having Russia extend up to it’s border. Turkey has already committed to selling electricity to Georgia after this conflict started.
On the other side of the Black Sea, there’s Bulgaria and Romania, both of which have strong anti-Russian movements.
On the other side of Russia (separated by Belarus) is Poland, which has a very strong anti-Russian sentiment. And, of course, there’s the Baltic states, where (up until this latest Georgian thing) one of the big issues was tearing down remnants of Russian occupation.
And, of course, there’s China. Some elements of Chinese government have been coveting the depopulating region of Siberia as a new home for the 1.1 billion Chinese currently crammed into China. Further, by invading Georgia, Russia just stole China’s glory at China’s Olympic coming-out party. That may be a more volatile combination than what is generally recognized.
So, while Russia may not have any major active conflicts, other than the one in Georgia, going on right now, Russia is surrounded by countries that largely hate Russians, and which might support the Georgians. If I was a Russian commander, I wouldn’t bet that those other countries wouldn’t get involved. That would sap Russian “horsepower” in a hurry.
Would Turkey or any of those other countries you mentioned be willing to become involved in a war with Russia in support of Georgia? If the answer is no, then their support is next to meaningless. All Russia has to do is simply steamroll over the opposition and wait for the condemnations to die down. They have the forces to do so as was the case in Chechnya and they certainly have the funding to ignore the outside world (thank you $4.50 for a gallon of gas).