In a 1991-92 war with Georgia, the breakaway republic declared independence with their capital as Tskhinvali, though the region has not been recognized as a nation by any country in the United Nations. The purpose of breaking away is seen as a desire to unify with ethnic brethren in North Ossetia Alania, which is part of the Russian Federation. In the time since, Georgia has protested Russia's role as a peacekeeping force in the region, saying it's not a neutral party in the conflict. About 70 percent of the region's inhabitants have been furnished with Russian citizenship, and more than half of its budget comes from Russia.
So when Georgia sent troops into the breakaway republic -- which is peppered with ethnically Georgian towns as well as Ossetian ones -- Russia responded with heavy force, using the disputed peacekeeping mission and Russian citizenship of regional residents as justification. The onetime Soviet republic of Georgia was also encountering conflict with Russia far from Ossetia in the Black Sea, and Russia had sent thousands of troops into Abkhazia, another Russian-supported breakaway region that has no international recognition.
Russia has the fourth largest active military force in the world, putting Georgia -- which is 80th on the list -- at a great disadvantage. As conflict escalated, the U.S. military intervened to get 2,000 Georgian troops quickly back from Iraq duty.
It's important to keep in mind that Georgia and Russia have been at each other's throats over more than Ossetians. Georgia's desire to join NATO has irked Russia, the Georgian government is unabashedly pro-U.S. with a pro-Western foreign policy, and a 2006 spy scandal took relations to the breaking point.
