The outcome of six grim days of bloodshed in the Caucasus has triggered an outpouring of the most nauseating hypocrisy from western politicians and their captive media. As talking heads thundered against Russian imperialism and brutal disproportionality, US vice-president Dick Cheney, faithfully echoed by Gordon Brown and David Miliband, declared that "Russian aggression must not go unanswered". George Bush denounced Russia for having "invaded a sovereign neighbouring state" and threatening "a democratic government". Such an action, he insisted, "is unacceptable in the 21st century".

Could these by any chance be the leaders of the same governments that in 2003 invaded and occupied - along with Georgia, as luck would have it - the sovereign state of Iraq on a false pretext at the cost of hundreds of thousands of lives? Or even the two governments that blocked a ceasefire in the summer of 2006 as Israel pulverised Lebanon's infrastructure and killed more than a thousand civilians in retaliation for the capture or killing of five soldiers?

You'd be hard put to recall after all the fury over Russian aggression that it was actually Georgia that began the war last Thursday with an all-out attack on South Ossetia to "restore constitutional order" - in other words, rule over an area it has never controlled since the collapse of the Soviet Union. Nor, amid the outrage at Russian bombardments, have there been much more than the briefest references to the atrocities committed by Georgian forces against citizens it claims as its own in South Ossetia's capital Tskhinvali. Several hundred civilians were killed there by Georgian troops last week, along with Russian soldiers operating under a 1990s peace agreement: "I saw a Georgian soldier throw a grenade into a basement full of women and children," one Tskhinvali resident, Saramat Tskhovredov, told reporters on Tuesday.

Might it be because Georgia is what Jim Murphy, Britain's minister for Europe, called a "small beautiful democracy". Well it's certainly small and beautiful, but both the current president, Mikheil Saakashvili, and his predecessor came to power in western-backed coups, the most recent prettified as a "Rose revolution". Saakashvili was then initially rubber-stamped into office with 96% of the vote before establishing what the International Crisis Group recently described as an "increasingly authoritarian" government, violently cracking down on opposition dissent and independent media last November. "Democratic" simply seems to mean "pro-western" in these cases.

The long-running dispute over South Ossetia - as well as Abkhazia, the other contested region of Georgia - is the inevitable consequence of the breakup of the Soviet Union. As in the case of Yugoslavia, minorities who were happy enough to live on either side of an internal boundary that made little difference to their lives feel quite differently when they find themselves on the wrong side of an international state border.

Such problems would be hard enough to settle through negotiation in any circumstances. But add in the tireless US promotion of Georgia as a pro-western, anti-Russian forward base in the region, its efforts to bring Georgia into Nato, the routing of a key Caspian oil pipeline through its territory aimed at weakening Russia's control of energy supplies, and the US-sponsored recognition of the independence of Kosovo - whose status Russia had explicitly linked to that of South Ossetia and Abkhazia - and conflict was only a matter of time.

The CIA has in fact been closely involved in Georgia since the Soviet collapse. But under the Bush administration, Georgia has become a fully fledged US satellite. Georgia's forces are armed and trained by the US and Israel. It has the third-largest military contingent in Iraq - hence the US need to airlift 800 of them back to fight the Russians at the weekend. Saakashvili's links with the neoconservatives in Washington are particularly close: the lobbying firm headed by US Republican candidate John McCain's top foreign policy adviser, Randy Scheunemann, has been paid nearly $900,000 by the Georgian government since 2004.

But underlying the conflict of the past week has also been the Bush administration's wider, explicit determination to enforce US global hegemony and prevent any regional challenge, particularly from a resurgent Russia. That aim was first spelled out when Cheney was defence secretary under Bush's father, but its full impact has only been felt as Russia has begun to recover from the disintegration of the 1990s.

Over the past decade, Nato's relentless eastward expansion has brought the western military alliance hard up against Russia's borders and deep into former Soviet territory. American military bases have spread across eastern Europe and central Asia, as the US has helped install one anti-Russian client government after another through a series of colour-coded revolutions. Now the Bush administration is preparing to site a missile defence system in eastern Europe transparently targeted at Russia.

By any sensible reckoning, this is not a story of Russian aggression, but of US imperial expansion and ever tighter encirclement of Russia by a potentially hostile power. That a stronger Russia has now used the South Ossetian imbroglio to put a check on that expansion should hardly come as a surprise. What is harder to work out is why Saakashvili launched last week's attack and whether he was given any encouragement by his friends in Washington.

If so, it has spectacularly backfired, at savage human cost. And despite Bush's attempts to talk tough yesterday, the war has also exposed the limits of US power in the region. As long as Georgia proper's independence is respected - best protected by opting for neutrality - that should be no bad thing. Unipolar domination of the world has squeezed the space for genuine self-determination and the return of some counterweight has to be welcome. But the process of adjustment also brings huge dangers. If Georgia had been a member of Nato, this week's conflict would have risked a far sharper escalation. That would be even more obvious in the case of Ukraine - which yesterday gave a warning of the potential for future confrontation when its pro-western president threatened to restrict the movement of Russian ships in and out of their Crimean base in Sevastopol. As great power conflict returns, South Ossetia is likely to be only a taste of things to come.

s.milne@theguardian.com