Georgia's attempt to re-take a rebel region by force is a gamble by its leader that he can still count on Western support as he tries to thwart Russian efforts to regain influence over the ex-Soviet republic.
Analysts said the escalating conflict in South Ossetia risked major consequences for a region that has become a test of the post-Cold War balance of power, as well as a key energy transit point for Europe which needs oil and gas from Asia.
Georgian President Mikheil Saakashvili was welcomed by the West as a fresh, reform-minded leader when he led a revolution in 2003 and was elected the next year, making Nato membership his priority as he tried to escape the orbit of Moscow.
But James Nixey, an analyst at the Royal Institute of International Affairs in London, said Saakashvili had worried Western capitals with his tendency to overreact when provoked.
That was shown when he used force last year to quash anti-government protesters and again now in the conflict in South Ossetia, he said.
"He is in big danger of losing the cachet he built up for himself in being pro-Western and the restraint he has often shown in the face of provocation by Russia," Nixey said.
"If he is going to start a war, he is going to lose the support of a lot of friends in the West."
Long-standing tensions over South Ossetia exploded on Friday when Georgia tried to assert control over the region with tanks and rockets, and Russia sent forces to repel the assault.
Tomas Valasek, foreign policy director at the Centre for European Reform, said Saakashvili had little choice but to take decisive action.
He said Russia's growing influence in South Ossetia and in another breakaway region, Abkhazia, was steadily undermining Georgia's hopes of joining the Nato military alliance and putting itself firmly in the Western camp.
"At the end of the day the Georgians realise that time is not on their side and they could not let South Ossetia and Abkhazia become even more messy and Russian influence even stronger," Valasek said.
Analysts said Saakashvili's gamble in launching military action against the rebels could trigger a David-and-Goliath war between his country and its powerful neighbour Russia, and it was far from certain that the West would come to his rescue.
"He has had plenty of warnings from the West that it won't pull any chestnuts out of the fire for him so I don't think he can count on the cavalry riding in," said Fraser Cameron of the EU-Russia centre in Brussels.
John Pike, director of globalsecurity.org, a US military information website, said Saakashvili could probably expect words of Western backing but perhaps nothing more than that.
"The Russians hope he will get more than verbal support," he said. "The Russians want a more direct confrontation with the West and I hope the Bush administration has the wisdom not to give them that satisfaction."
The newly confident Russia wanted a confrontation to justify an overhaul of its outdated military equipment, Pike said.
The United States said it supported Georgia's territorial integrity and called on all parties to avoid conflict. Nato and the European Union also urged all sides to halt the violence.
Georgia's ambition of joining Nato was put on hold in April when alliance members were split at a summit between supporters of accession for Georgia and Ukraine and other countries which feared such a move would antagonise Russia.
Neither country was offered a firm membership plan but they were told instead they would join Nato in the future.
Nixey said Saakashvili could be jeopardising his country's chances of getting into the alliance: "Ultimately his Nato ambitions could go out of the window."
Strategic Forecasting Inc., based in the United States, said Georgia represented "the hottest flashpoint in Western-Russian relations" as it was the easternmost foothold of Western power.
"What is being decided here is whether bordering Russia and simultaneously being a US ally is a suicidal combination. Whichever way this works out, the dynamics of the entire region are about to be turned on their head," it said in a note.