The Russian tank columns rumbling into Georgia reveal the anger of a tiger finally swatting the mouse that has teased it for years. South Ossetia may seem as distant, trivial and complicated as the 19th-century Schleswig-Holstein question but Russia's fury is about much more than the Ossetians. The Caucasus matters greatly to the Russians for all sorts of reasons, none greater than the fact that it now also matters to us.

The troubles in Georgia are not the equivalent of an assassinated archduke in Sarajevo. But historians may well point to this little war, beside the spectacular Olympic launch of resurgent China, as the start of the twilight of America's sole world hegemony. If the new Great Game is for the oil of the Caucasus and Central Asia, the West may be in the process of losing it.

I've been visiting Georgia since the fall of the Soviet Empire in 1991. I've known all three Georgian presidents since independence, and witnessed the wars and revolutions of the Caucasian tinderbox. In 1991 the chief of the Georgian partisans in the first Ossetian war, a dentist turned warlord, drove me up to villages around Tskhinvali, highlands of lusciously green beauty, where a vicious war between Georgian and Ossetian farmers was being waged with the ferocity of intimate neighbours, using comically armoured tractors instead of tanks.

My Georgian hosts leant their guns against a tree and took me to an open-air feast at a table stacked with delicacies in honour of a local boy killed that day. During the long drunken banquet I asked where the boy was buried. “He hasn't been buried,” replied my host, “he's under your feet.” Paling, I looked and there he lay, stretched out under the table, cradled with bouquets of flowers.

Vladimir Putin's mastery checkmates the West

Michael Binyon says Russia has been biding its time - but its victory in Georgia has been brutal and brilliant

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BACKGROUND

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To understand this week's events, we must travel back a thousand years: long before Russia existed, Georgia was a Christian-warrior kingdom. The Caucasus was the natural borderland of the three great empires of the Near East: the battlefield between Orthodox Russia, the Islamic Ottomans and Persians. In 1783 the embattled King Eralke II was forced to claim the protection of Prince Potemkin, Catherine the Great's partner-in-power. Between 1801 and 1810 Russia swallowed the last Georgian principalities. In 1918 Georgia enjoyed independence for three years before Stalin seized it back for Moscow.

No one understood its ethnic complexity and strategic significance like Stalin, that Georgian romantic turned Russian imperialist, who had been born in Gori, the town that has been overrun by Russian forces and where a marble temple now stands over the hut where he was born. The Ossetians who straddled the border had early sought Russian alliance, earning Georgian disdain. Hence Stalin was accused by his enemies of being an Ossetian: his father was of Ossetian descent, though long since Georgianised. Stalin drew the borders of the Soviet republics to ensure Georgia contained autonomous ethnic entities, South Ossetia, Abkhazia and Adzharia, through which Moscow could keep Georgia in order.

When that proud, cocky bantam, Georgia, became independent in 1991, the Russian double-headed eagle was humiliated. Ever since, Russian interference and skulduggery has bedevilled Georgia. Russia encouraged southern Ossetia to establish a statelet within Georgia, whose inept, insane first President, Zviad Gamsakhurdia, had inflamed ethnic tensions. As Ossetians fought Georgians who themselves rebelled against Gamsakhurdia, I sat in his office: he was a Shakespearean scholar and quoted King Lear to me.

Gamsakhurdia was either murdered or committed suicide. In 1993, his successor Eduard Shevardnadze, the former Soviet Foreign Minister and Politburo member, lost Abkhazia in another bloody Russian-orchestrated war. But Shevardnadze won the peace. Georgia, which had longed to be part of Europe, embraced Western democracy and US friendship. Yet Shevardnadze recognised the limits of Georgian defiance, once telling me as we flew in 1993 in his plane to make peace with the Kremlin: “The destiny of Russia is reflected in the Caucasus like the rays of the sun are reflected in a drop of water.”

Old, autocratic Shevardnadze was toppled in the Rose Revolution of 2003 by an energetic and decent if impulsive US-educated lawyer, Mikhail Saakashvili, who hoped to escape Moscow for ever by joining the EU and Nato - as did Russia's huge neighbour, Ukraine. This prospect of encirclement by triumphant America infuriated Russia. Imagine if newly independent Wales cockily joined the Warsaw Pact.

Russia is no longer the spineless giant of the Nineties: Vladimir Putin's musclebound, oil-fuelled authoritarian regime has aggressively reinvigorated Russia. He had already shown his ruthless determination to master the Caucasus by crushing Chechnya. Nato in Georgia would have made that meaningless. The Kremlin has used its clients, Abkhazia and Ossetia, as Trojan Horses to ruin Tbilisi's independence - recently raising the tension by offering Russian passports to all Ossetians and testing Georgian resolve with cross-border skirmishing: the trap of a practised imperial power.

Georgia is not guiltless: most Georgians I know care little about Ossetia even though it is part of sovereign Georgia. But in order to join Nato, President Saakashvili wanted to settle Georgia's instability by reclaiming Ossetia and Abkhazia. By seizing Tskhinvali, he took one hell of a gamble that Russia wouldn't intervene. Georgia is paying a high price for this. To finish this vicious circle, Russian attacks show how badly Georgia needs EU/Nato protection, yet Georgia will never get it while embroiled in fighting.

The retaking of Ossetia is a minor part of the Russian campaign. More significant is the attack on Georgia proper, which reasserts Russia's hegemony over the Caucasus, assuages the humiliations of the past 20 years, subverts Georgian democracy - and defies and defangs American superpowerdom. The swaggering arrival of Vladimir Putin, now the Prime Minister, across the border, macho in his tight jeans and white leather jacket, shows he, not President Medvedev, remains Russia's paramount leader.

This war is really a celebration of ferocious force in the realm of international power, a dangerous precedent. The West must protest with unified resolve; Russia both despises Western hypocrisy and craves Western approval. Georgian democracy and sovereignty matter. So do our oil supplies: the West built a pipeline to bring oil from Azerbaijan and Central Asian across Georgia to Turkey, free of Russian interference.

Russia's clumsy ferocity could ignite a Caucasian tinderbox that even Moscow cannot extinguish. But faced with Western outrage, the Kremlin might toss Stalin's words back at President Bush: “How many divisions has the Pope?” None: Washington and London are not sending the 101st Airborne or the SAS.

Russia, which appears to be pushing its tanks into Georgia to overthrow its democratically elected president, has demonstrated gleefully the limits of US power and Moscow's historic destiny as regional hegemon and restored 21st-century superpower. The Empire has struck back and shaken the order of the world.

Simon Sebag Montefiore is the author of Young Stalin. His latest book is a novel, Sashenka

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