So why attack secular Iraq rather than an Islamic country such as Saudi Arabia or Iran? Because, as Friedman bluntly argued, the US could. He construed the attack as an opportunity to export US-style democracy to the Arab world, imagining that the toppling of Saddam would unleash democratic movements throughout the region.

Pressed gently, Friedman answers all my questions. After all, the Minneapolis-born pundit is, in his own words, 'Minnesota nice': he never hits back at his critics. By phone, he has the relaxed bonhomie of a country club regular (allusions to golf, his favourite pastime, pepper his writing) and the upbeat temperament of an adman.

His writing is studded with company and brand names. With their glib metaphors and catchphrases, his columns can read like advertising copy. 'To name something is to own it,' he says.

The jingle 'hot, flat and crowded', for example, describes the convergence of climate change, globalisation and overpopulation that defines our 'energy-climate era', he says.

In The Lexus and the Olive Tree (1999), his first book-length paean to globalisation, Friedman argued that countries invest in peaceful futures by accepting the 'golden straightjacket' of market liberalisation. Enmities arising from tribal, national and historical loyalties (symbolised by 'the olive tree') disappear, he contended, when societies open up to global markets and are in thrall to consumerism ('the Lexus').

Lexus argued the Golden Arches theory of conflict prevention: countries with McDonald's outlets don't fight each other. Shortly after the book was published, the US bombed Yugoslavia, thereby torpedoing the theory. But Friedman protests he 'was not laying down physics but a principle of a broad trend'.

The World is Flat (2005) conceived of the globalised world in terms of 'flatness'. The dotcom revolution and the interdependence of markets, technologies and populations levelled the economic playing field, Friedman argued, giving people unprecedented access to the world market.

He rejects the argument of Nobel laureate economist Joseph Stiglitz that globalisation has made the world less flat by furthering inequalities in the developing world. 'Socialism was a great system for making people equally poor and what markets do is make people unequally rich. The countries that are least globalised - North Korea, Cuba, Sudan pre-oil - are also the poorest,' he says.

As an internationally syndicated writer, Friedman benefits from the flat world. 'This is the golden age of being a columnist. Your opinion can go more places and reach more people. It is the most fun legally you can have that I know of.'

In the Middle East, his photo byline is so well-known that he's constantly approached in the streets. Gail Collins, a former opinion editor at The New York Times, has likened travelling there with Friedman to walking through a mall with Britney Spears. It was through Friedman that King Abdullah of Saudi Arabia (then crown prince) floated his 2002 proposal that Arab states give full recognition to Israel if it withdraws to pre-1967 borders.

Friedman's intimate voice, Panglossian forecasts and gimmicky phrases make him a winning middle-brow commentator. But his subjects often call for more sceptical treatment. Indeed, as the Iraq war foundered, he refused to pronounce it a disaster, emphasising the importance of 'the next six months' - even as 2003 became 2006.

The costs of the war, he now admits, have been staggering. 'I wrote what I wrote at the time because I believed it. I'm just hoping the phase it's in right now will produce a decent outcome. Iraq may be coming out of this tailspin. Maybe a year from now things will look different.'

Having reported on the sectarian conflict in Lebanon in the early 80s, Friedman experienced 'a struggle between hope and experience - the experience of Lebanon but also the hope, particularly post-9/11, that the Middle East could give birth to a different kind of politics.'

Hope won out, leading him to embrace the Iraq war. But he's not inclined to wring his hands or navel gaze: 'My eyes tend to be focused straight forward and not behind. It's the only way you can really survive if you're sitting where I sit and having the number of people commenting on what you do.'

Hot, Flat, and Crowded is likely to draw fire from Democrat and Republican partisans alike, with both parties convinced oil prices are the most pressing environmental issue of the presidential race.

'Our problem isn't too high gas prices any more than a crack addict's problem is too high crack prices,' Friedman says.

To lower prices and reduce US reliance on foreign oil, Republican hopeful John McCain proposes lifting restrictions on drilling, and Democrat candidate Barack Obama recently reversed his opposition to offshore oil drilling.

'You'd have to have your head examined to be optimistic that a campaign like this is preparing the country for what we need by way of a revolutionary change of energy systems,' Friedman says.

His diagnosis? 'We're addicted to a dirty fuel system based on fossil fuels of coal or natural gas. In a world that's getting hot, flat and crowded, that addiction is increasingly toxic. It is driving five problems way beyond their tipping point - and they are climate change, petrodictatorship, energy and natural resource supply and demand, biodiversity laws and energy poverty.'

Friedman says the past two decades have seen the rise of 'dumb as we wanna be' politics in the US: the reluctance of leaders to address multi-generational problems.

'We've lost our way as a country, and green for me is how we get our groove back - focusing on a green agenda the way we once did on a red anti-communist agenda.' Going green is also a security imperative, in Friedman's analysis. US companies bolster the oil wealth of Middle Eastern states, which sponsor Islamic fundamentalism. Developing renewable energy technologies would make oil cheaper, he says, forcing Arab countries to build their economies through technological innovation, entrepreneurship and education.

Friedman became interested in the Middle East after travelling to Israel with his parents in 1968, aged 15, to visit his elder sister, then on a student exchange. After studying Arabic language and literature at Brandeis University, he earned a master's degree in Mideast studies at Oxford. While in Britain he met his wife, Ann Bucksbaum, heiress to a multibillion-dollar shopping centre fortune. A board member of Conservation International, she also edits his columns.

Friedman became the Times newspaper's Beirut bureau chief himself in 1982, moving to Jerusalem two years later. He openly identified as Jewish in his dispatches from the Middle East, which most of his Jewish-American colleagues avoided for fear of seeming biased. 'I wasn't a self-hating Jew,' he says.

The editor of Haaretz once joked to Friedman that the Israeli newspaper ran his column because he was the only optimist it had. His upbeat outlook is a product of his upbringing, Friedman says.

'I had a kind of Leave it to Beaver childhood. I always brought that Minnesota optimism to the world.' But life did not always resemble a sitcom. When Friedman was 19, his father Harold, a ball-bearing salesman and keen golfer, died of a heart attack. Harold Friedman had attained local celebrity status for trailing his teenage son during his high school golf matches. Still his father's son, Friedman contributes regularly to Golf Digest and toys with the idea of writing a golf book.

On turning 55 this year, Friedman qualified for the seniors' championship at his club. As the first competitive match he had played since high school, it unleashed his sentimental side.

'A huge limb broke off a tree adjacent to the tee and just came crashing to the ground,' he recalls. 'I suddenly had this realisation that that was my Dad, that he was watching. It made me start to cry. I think the old guy was very proud of me.'

His mother Margaret died this year, aged 89. In an obituary column, he called her 'the most uncynical person in the world'. A champion bridge player, Margaret Friedman served in the navy during the second world war, qualifying for the GI Bill loan with which the Friedmans bought their home. Thomas Friedman has never lost faith with the chestnut of America as a land of preferment. 'I thank God every day that I was born in a country that has given me these opportunities,' he says.

The US remains more a force for good than ill for Friedman. It spends more on Aids relief in Africa than any other country, he says, adding it was the Bush administration that pushed for UN sanctions against Zimbabwe (blocked by China and Russia) in July.

'I don't think the Iraq war is the be all and end all definer of the United States today,' he says. Which is perhaps another way of saying it shouldn't be the sole definer of Thomas Friedman.

Writer's notes

Name: Thomas Friedman

Genre: political commentary

Latest book: Hot, Flat, and Crowded: Why the World Needs a Green Revolution - and How We Can Renew Our Global Future (Allen Lane; Farrar, Straus and Giroux)

Age: 55

Family: Married to Ann Bucksbaum, with two daughters, Orly, 23, and Natalie, 20

Books: From Beirut to Jerusalem (1989); The Lexus and the Olive Tree (1999); Longitudes and Attitudes: Exploring the World Before and After September 11 (2003); The World Is Flat: A Brief History of the Twenty-first Century (2005)

Other jobs: Host of Discovery Channel documentaries

What the papers say: 'Friedman has converted to green faith and to environmental trumpery, but in a more nuanced and optimistic way than most of his fellow travellers ... adopting instead a realistic and economically literate position.' The Sunday Telegraph on Hot, Flat, and Crowded

Quote: 'It is hard for France to maintain a 35-hour work week when China and India have invented a 35-hour day.' - from Hot, Flat, and Crowded