"America has no empire to extend or utopia to establish," the US President, George Bush, told graduating officers at the West Point military academy in June last year. "The 20th century ended with a single surviving model of human progress," Mr Bush declared, but cautioned that democracy was not a vision the United States could "impose". Evidently, Mr Bush believes the war in Iraq has changed all that. In a major policy shift last week, Mr Bush presented a sweeping vision of a US-led "global democratic revolution". At stake in Iraq is not merely the liberty of the Iraqi people, but the global export of the ideology of freedom, as defined by Mr Bush's inner circle.

This is no simple extension of his "axis of evil", which singled out a handful of isolated, pariah states. Pointedly, Mr Bush included China in the company of such authoritarian regimes as Cuba, Zimbabwe, Burma, Syria, Iran, Saudi Arabia and Egypt, which are failing Washington's democracy test. Mr Bush lectured the Chinese leadership on their people's desire for "liberty, pure and whole". He dismissed substantial reforms which have accompanied China's free market transformation, as a "sliver" of freedom. Mr Bush's patronising tone will be most unwelcome in Beijing and will complicate diplomacy in Asia. Key US allies in the region, including Australia, are seeking to balance their historic allegiance to Washington with increasingly important ties to China, and its rapidly growing economy.

Where the global democratic revolution will take the US, in a practical sense, is unclear. Since World War II, successive US governments have pursued a dual-track foreign policy. One approach is liberal and seeks to build global order around alliances of free market democracies. The other is pragmatic, conceding America's strategic interests can, at times, be secured through warm ties with "friendly tyrants". In the Middle East, for example, America's expedient relationship with the oppressive monarchy in Saudi Arabia - a major oil supplier and host to US forces - has been a constant reminder of the contradictions of preaching democracy while accommodating autocracies.

"In the long run, stability cannot be purchased at the expense of liberty," Mr Bush declared last week, expressly repudiating more than half a century of selectively indulging dictators in the Middle East. Whether Mr Bush can close the yawning gap between idealism and "realpolitik" is questionable. Immediately, Mr Bush has put himself at odds with the realities of his "war on terrorism", which relies heavily on the co-operation of a string of autocratic regimes in the Islamic world. While Mr Bush insists Islam and democracy are not incompatible, he overstates token reforms in Saudi Arabia, for example, and underestimates the potential for terrorism there. The suicide bombings in Riyadh on Saturday make this point. More broadly he glosses over rising anti-US sentiment in the Arab world.

Mr Bush has recast Iraq as the centrepiece of his global democratic push. Yet, Iraq is also emerging as the battleground in a broader anti-American terror campaign. The rush of foreign jihadis into Iraq carries a potent warning to Washington of the risks of pushing further. This is a reality Mr Bush seems determined to ignore.