Since the collapse of the Soviet Union 15 years ago, the phrase "cold war" - along with the "free world" and "eastern bloc" labels for each side - have largely been confined to historical discourse. These terms, suggesting a titanic clash of ideas between two clearly defined camps, are now making a disturbing comeback, usually in connection with China.
When they are not thinking about the Middle East and the threat of Islamic extremism, hawks in Washington compare the strategic and ideological challenge of China's rise today with the threat posed to the west by the Soviet Union in its 1960s heyday. Given the recent rapprochement between Beijing and Moscow, there is also a plausible argument to be made that the US superpower will soon be waging a cold war against a new "axis of authoritarianism".
Relations between Russia and China - each has a permanent seat on the United Nations Security Council and together they dominate the Eurasian landmass - have not been so warm since the 1950s.
Vladimir Putin, the Russian president, has just had his fifth meeting in 12 months with Hu Jintao, his Chinese counterpart. On a visit to Beijing last week, Mr Putin made a $10bn (£5.7bn) promise to build two pipelines from Russia to supply China with the gas it urgently needs.
The two countries have recently boosted trade, held a joint military exercise, resolved the territorial disputes along their 4,300km border and found a common interest in curbing the influence of the US superpower. In the words of Russia expert Bobo Lo of the Chatham House think-tank in London, China and Russia have developed a "genuinely businesslike strategic partnership".
Their strategy, furthermore, in many ways directly contradicts the US National Security Strategy released this month. The opening sentence of the US document - "It is the policy of the United States to seek and support democratic movements and institutions in every nation and culture, with the ultimate goal of ending tyranny in our world" - is anathema to Beijing and Moscow.
From Belarus to Burma, both governments support dictators, military juntas and authoritarian rule. A Pentagon report alleging that the Russian ambassador in Iraq gave Saddam Hussein intelligence about US military strategy in the run-up to the invasion of Iraq will do little to inspire western confidence in Russia.
US policymakers alarmed by the prospect of a new "eastern bloc" can draw comfort from the continuing western focus of both Russian and Chinese foreign policy and from the lingering antipathy between the Russian and Chinese peoples.
Most Russians see themselves as Europeans; many harbour atavistic fears that Asiatic hordes will one day sweep across the border to reclaim ancient Chinese territory in what is now the underpopulated Russian far east. Previous Sino-Russian announcements of ambitious energy schemes have produced few results.
Globalisation and the resulting linkages between the Chinese, Russian and western economies also reduce the likelihood of another confrontation between rival superpowers.
In an article this month entitled "Is China the nemesis in a new cold war?" the US-based Asia scholar Emmanuel Pastreich concludes that the US-China contest, far from being a cold war, is akin to the global struggle over markets, technology and cultural authority between the US and its ally Britain from 1910 to 1970.
Fears of a US-China cold war, however, are not confined to the fringes of US politics. James Baker, the former US Treasury secretary and secretary of state, criticised US trade protectionists and warned an audience of business leaders in Hong Kong last week that economic ties alone were no guarantee of peace, as shown by the "golden age" of interdependence before the first world war.
"Should Washington and Beijing slip into confrontation, everybody will lose," he said. "It would be nothing less than tragic were the world, after emerging from one cold war, to plunge into another." We are not there yet, but this is a warning both sides should heed.
