MOSCOW Conflict between Georgia and an increasingly assertive Russia has long been in the making and there is no certainty it will end quickly despite the enormous disparity of their forces.
Tensions exploded on Friday when Georgia tried to take back control of the rebel region of South Ossetia with tanks and rockets, and Russia sent forces to repel the assault. Fighting raged around South Ossetia's capital, Tskhinvali.
Conflicts between Georgia and South Ossetia and another breakaway republic, Abkhazia, began when the Soviet Union broke up almost two decades ago. Violence has flared occasionally, but signs have increasingly pointed to a major showdown.
The roots of the recent conflict are threefold, said analyst Svante Cornell, co-director of the Stockholm-based Institute for Security and Development Policy and an expert on Georgia.
"It boils down to Kosovo independence, NATO's Bucharest summit and possibly also Russian internal politics and the transfer of power," Cornell told Reuters by telephone.
In February, Russian diplomats said Kosovo's unilateral declaration of independence from Serbia would stir up strife in the Balkans and linked Kosovar status to separatist areas Abkhazia and South Ossetia. Western states backed Kosovo.
In Romania in April, NATO leaders made a vague pledge to invite ex-Soviet Georgia and Ukraine into the alliance at some future point. In response, then-president of Russia Vladimir Putin promised more support for Abkhazia and South Ossetia.
In May, Putin stepped down after two terms and his hand-picked successor Dmitry Medvedev was inaugurated president. Putin did not leave power though, and soon he was appointed prime minister and is still seen as the leader of the country.
Cornell said Russia has seized upon a moment to assert itself in South Ossetia when Europe is unwilling to anger at Moscow and the United States is distracted by domestic elections. He suggested Georgia had fallen into an Ossetian provocation.
"Irrespective of who triggered this recent action, the general direction of Russian policy is clear, which is: We are taking control of these territories, and we're not even pretending that we're not," Cornell said.
Unlike Abkhazia on the Black Sea coast, South Ossetia is not a wholly integral territory with congruent borders. Instead it is a checkerboard of villages and towns in the foothills of the Caucasus mountains, interspersed with islands of Georgia proper.
The majority of South Ossetia's 70,000 people are ethnically distinct from Georgians and look to Moscow rather than Tbilisi.
Most of the violent clashes in the region this year had been over nearby Abkhazia, with troop deployments, downings of drone airplanes and Russian warplane incursions into Georgian airspace all leading Tbilisi to say war was "very close".
When a muscular Georgian military response came on the heels of what Cornell and security analyst Pavel Felgenhauer both called Ossetian provocations, the logistical advantage Tbilisi enjoyed over Moscow in the fight became apparent.
"Turning the tide of a Georgian offensive would mean a massive invasion by Russian forces," said Felgenhauer.
"They would need to deploy crack Russian troops on the battlefield, and that does not guarantee victory over Georgia because you can't deploy much."
On paper, Russia has an overwhelming military advantage over Georgia. Russia has 140 million people compared to fewer than five million in Georgia.
But Georgia and South Ossetia have the fortifications of the Caucasus mountains to the north. As Russia has learned in Chechnya, it is not easy terrain to fight in.
Only one road runs south from Russia into South Ossetia. There are no military-capable airstrips and snows from October through May close the mountain passes.
Christopher Langton, defence analyst at the International Institute for Strategic Studies in Britain, said Russia did have the military capability, "to secure a corridor from Tskhinvali back through the Roki tunnel and to secure Tskhinvali itself."
But not everyone is convinced. Felgenhauer said Georgia's U.S.-trained army was stronger than many believed and had trained for just such a scenario.
"Massive Russian intervention would mean it's going to be a long war, a bloody war, with an unpredictable outcome, because Ossetia is geographically separated from Russia."
"It's a hell of a logistical nightmare to try and take and keep South Ossetia against a rather fine Georgian military," Felgenhauer said.
(Additional reporting by Luke Baker in London; Editing by Matthew Tostevin)