These are all excellent answers. The conflict goes much farther back in time, however. Georgia became a sort of vassal state to Russia in the 18th Century, partly for protection against the Ottoman Empire and partly because they could not protect themselves against the Russians anyway. Ethnic and nationalist tensions between Georgia and Russia have surfaced continuously ever since. Georgia, Armenia and Azerbaijan united as the Transcaucasion Federation in 1917, Georgia becoming independant the following year. In 1922 they were forcibly annexed by the USSR.
The disturbing thing about the current unrest to me is the excuse used by Putin to explain the invasion of South Ossetia and Abkhazistan, that of the Russian national duty to "protect" Russians living in these areas. The Abkhazi are not Russian, neither are the Ossetians, and neither ethnic group has expressed any interest in being part of Russia again. The North Ossetians, living in Russia, want to seperate from the larger country and unite with the South Ossetians as an independant nation.
The excuse of protecting Russians living in neighboring countries is the same excuse Hitler gave for annexing Czechoslovakia and invading Poland, to "protect" Germans living in a country he wanted.
Georgia and Russia have had tension that goes way back in history. Initially, Georgia had gained independence after the 1917 Russian Revolution, but lost the independence after Russia invaded it and made it a part of the USSR, and a very important satellite nation. In 1991, with the fall of the USSR, Georgia regained its independence. A part of Georgia (the provinces of South Ossetia and Abkhazia), had separated from Georgia to become allied more with Russia, and the fight for this area is one of the reasons that there is currently a conflict. In addition to the contest for this land, Georgia’s desire to become a member of NATO is causing problems for Russia – as the alliance undermines the dominance of Russia in the east.
In addition to the great response from ms-mcgregor, there is little doubt as to why Russian aggression is being imposed on the nation of Georgia. Russia is definitely trying to re-assert itself as an aggressive power, however political science teaches that observing "political timing" is crucial in order to understand the force of underlying intent. With the United States actively involved in the war on terror, Russia has re-gained some of its strength. The fact that the United States' attentions have been focused on terrorism, Russia had the "political timing" it needed to infringe on territory that was once under their "iron curtain".
Russia has been very sensitive to the fact that many of its former soviet dominated states ( Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia ) have recently joined NATO. They fear that Western infuences are encircling their county.
Georgia recently asked for NATO membership. Thinking this would keep his nation safe from Soviet aggression, Georgian president Georgia Mikheil Saakashvili allowed Georgian forces to drive across the border of South Ossetia, a secessionist region of Georgia with a large Russian population. It has functioned as an independently since the fall of the Soviet Union. Saakashvili obviously miscalculated his support from NATO, especially the United States. This lack of support from NATO and its allies allowed Russian forces to enter South Ossetia, defeat the main Georgian forces, and continue to extend their invasion into Georgia proper. The Russians want to communicate to the rest of the world that the weak Russia of the 1990's is gone and there is a new balance of power in the region. Georgia controls a large oil pipeline to the West and Russia itself is a large energy exporter. It is now obvious that Europe needs Russian oil, the United States needs Russian political support in other areas, and Russia knows this. Russians, especially Vladamir Putin, have also served notice that it will not allow Western influence to completely encircle their country.
Flash-forward to the past, Georgia was actually an independent state, but it soon fell to the Soviet Union in the 1920s after USSR invaded and occupied its lands. Georgia was actually a critical satellite state for USSR. But after the Soviet Union had broken up, it became an independent country, like Estonia, Latvia and Lithuania.
Also, many of Russia's former territories had already broke away from Soviet sphere of influence and joined NATO as a collective security against Russia. So, Georgia followed suit and formed a defensive alliance with NATO.
Looking at how US's resources are depleted by its military efforts during the US-Afghanistan War and also during the conflict with Iran, they have no position to intervene in Russian affairs. It gave Russia the chance to spread its sphere of influence.
Now that Georgia had gotten NATO membership, Georgian president Mikheil Saakashvili allowed its military forces to drive across the border of South Ossetia, which has a large Russian population and invade it. But, Georgia did not have any military support and so was left on its own. On the morning of August 8, Russian forces entered South Ossetia. Russian forces executed a swift and decisive counterattacking measure against the Georgian forces, and took them by surprise. Russia had defeated Georgia in South Ossetia and soon extended their offensive into Georgia proper. Soon, the world knew that the Soviet Union of the past was long gone, and now it was the meaner and tougher Russia that took its place, a warning to the world that Russia was not to be messed about. Russia wanted to eradicate Western capitalist influence away from its country and build its own "Russianalized" culture.