Several images from a week in Washington will last me a long time. Citizens surging over the Potomac bridges into DC before dawn. Black matrons beaming with damp-eyed pride as their favourite son was sworn in. The new President and his wife holding hands, taking the applause along Pennsylvania Avenue just before dusk. An entire bar united in derision whenever George Bush popped up on TV. And also, from last Sunday at the Lincoln Memorial, Bruce Springsteen and Pete Seeger performing the penultimate number of the inauguration concert, Woody Guthrie's folk anthem This Land Is Your Land.

Barack Obama, the then still President-elect, and his family were seated a few yards away on the improvised stage. Stretching away in front of Seeger and Springsteen stood a crowd of 400,000, me among them. For all the talk of bipartisanship and shared endeavour, I realised at that moment that after years of chinos and country clubs and in bed by 9pm, the cool guys are back in charge of the US. I can't tell you what a relief that is.

I like America. I like Springsteen. And I like folk music. To varying extents, I've been keeping quiet about all three for years. It feels good to get it out there and I've got Obama to thank. Americans don't do things by halves. Corporate greed, military might, massive federal phone-tapping, and now a super-cool political leader inspiring one generation and making it safe for others to express admiration for his country without risking exile from polite society. The British liberal-Left isn't all anti-American. Some of us are very fond of the place, not just the landscape and the people but the ideology too. We think the American Dream is a progressive narrative worth imitating. That said, these past eight years have tested that fondness to the limit.

And yet there have always been names you can invoke to give the bien pensant bigots pause for thought. Studs Terkel was one such. Arthur Miller was another. Obviously now Obama is the most argument-clinching of all. But the name I've used to defend America most often is that of Springsteen, because in Bruce I saw the America I wanted to believe existed. Here is a man of humble origin, 60 this year, who made his name and his pile and proceeded to use fame and fortune in exemplary fashion.

He has leveraged his status artistically, alternating big-sound rock and pop albums with darker acoustic material handling political themes, material that doesn't get radio airplay and can't make his record company very happy. And he has leveraged his status politically, to champion not just good and easy causes but often good and difficult causes, such as the troubles of Mexican immigrants, or rustbelt steel-workers.

Springsteen's identification with progressive politics has been gradual. He always sang about ordinary people salvaging dignity in the face of hardship, and Born in the USA, as everyone knows (except Ronald Reagan, who tried to co-opt it as a jingoistic anthem) is an anti-Vietnam war song, but not until The Ghost of Tom Joad in 1995, with its obvious debt to Steinbeck, its tales of vagrants and migrants, did Springsteen's songs become explicitly radical. Even now, his most recent albums, and his new one, Working on a Dream, released on Monday, are rarely overtly political, although the title track is reassuringly sleeves-rolled-up-for-a-better-tomorrow Obama-esque.

And yet when the Inaugural Committee was planning the the concert, the headliner they were always going to call, with a parade of superb black performers in between, was Springsteen. If Mary J.Blige and Beyoncé and the rest of R&B royalty speak to one vital strand of Obama's coalition, Springsteen speaks to two other equally important constituencies: middle-class white lefties like me, and traditional organised labour.

Springsteen had given concerts for Obama in swing states during the campaign, just as he had for John Kerry in 2004, when No Surrender had become an unofficial campaign song. Springsteen had helped to give the stamp of blue-collar approval to Obama, who sometimes looked at risk of being a bit too much the yuppie Harvard lawyer. “I spent most of my life as a musician measuring the distance between the American Dream and American reality,” Springsteen said at Cleveland's vote for change rally, “I believe Senator Obama has taken the measure of that distance in his own life and work.”

One of the endless talking heads popping up on the US networks last Tuesday said Obama had made it cool to be patriotic again. But that's not true. It has always been fine to be patriotic in America, and it has always been fine to be patriotic on the American Left. At the inauguration concert, no conflict existed between radical politics and patriotism. Indeed, Springsteen and Seeger and everyone else up there would say they were radicals because they were patriotic. When Master Sergeant Caleb Green sang The Star Spangled Banner, the crowd stood ramrod straight. Many men removed their hats. This was a liberal, intellectual crowd and for them patriotism and radicalism went hand in hand. I've always wished that were the case in Britain.

When I interviewed Springsteen for The Times not long after the twin towers were attacked, the Stars and Stripes flew from his garage roof in New Jersey. Maybe Paul Weller hoists the Union Jack in his front garden, but I doubt it. “The Right tries to co-opt everything that shows a pride in place,” Springsteen said. “I've always thought ‘No, that flag belongs to me'.”

At the inauguration concert Springsteen introduced Pete Seeger “as the father of American folk music”. Seeger was singing about environmental catastrophe and the plight of indigenous people when Sting and Bono were still dreaming of getting rich. My dad had a couple of Seeger albums; he was one of the first musicians I heard; through him I got into Guthrie and Dylan.

I didn't get into Springsteen until the late Eighties. If you were on the British Left in those days, displays of traditional masculinity were not condoned. So I allowed myself to be put off by what many fans liked, the machismo, the bandana, the singlet, the songs about cars (I quite like all that as well now - times change), the hard-pounding stadium rock. Then I heard Nebraska, ten bleak modern folk songs recorded in Springsteen's front room, still sublime 27 years after it was released, and the material was so good, so moving, I set about steeping myself in the rest of the oeuvre.

It was a brave move by Obama's people to have Seeger at that concert. A member of the Communist Party in the Forties, Seeger was subpoeaned by McCarthy in the Fifties. Ninety years old in May, still active, still stubborn, Seeger insisted he include the two most controversial verses of This Land is Your Land, including one that rails against a “private property” sign. And there sat the man about to become President, apparently relaxed to be identified with this Depression-era classic advocating something perilously close to socialism.

Springsteen has been a multimillionaire since Born to Run went big in 1975 and a global superstar since Born in the USA went stratospheric in 1984. Quite a feat, then, to remain a man of the people, but there's nothing Hollywood about him, no suggestion of dilettante radical chic, which is why he was a safe choice for the heartlands tuned into HBO last Sunday. A wife convicted of killing her husband last year offered in her defence that she had snapped when he insisted on turning off her new Bruce CD. “I mean, who doesn't like Springsteen, for God's sake?” the killer implored.

Her surprise illustrates the Boss's enduring popularity. He has sold 65 million albums in America and next Sunday will play at half-time in the Super Bowl to huge TV ratings. Grassroots America has kept faith with him because he doesn't sing about limos and hotels, he sings about Main Street characters and places. And because he can still write a great melody, and because he's a showman, with a great sense of fun, theatre and cheesy rock melodrama.

I remember his show at Wembley Arena in 2006. It was possibly the nadir of the Bush presidency, not long after Katrina, not long after Abu Ghraib. Springsteen was touring the Seeger Sessions material, his take on traditional songs repopularised by the eponymous old folkie. Being there came close to what I imagine believers feel at a charismatic church service, and not just because Springsteen's music has always been suffused with religious imagery and cadences, rather like Obama's oratory. It was also an affirmation that a compassionate America existed beyond the neglect of New Orleans and torture in Iraq.

The Rising, with which a black-clad Springsteen opened the inauguration concert, backed by a massed gospel choir in red, the song, hymn really, which played on loudspeakers throughout DC last Tuesday, is the Ascension myth as told through the eyes of a firefighter climbing a World Trade Centre tower on September 11. Springsteen saw straight away that a vital chapter in the story of that day was about staggering working-class heroism, a martyrdom.

I am an atheist, but I like the religiosity of Springsteen's writing, as I like the religiosity of much good political oratory. British popular songwriting is supremely witty, wonderfully observed at its best, from Arctic Monkeys back to Noël Coward. It is also often ironic, if not downright cynical, and sometimes the soul needs something uplifting, something that uses the language of grace and sacrifice and redemption.

“Look at my songs,” Springsteen said to me in our interview, “the verse is the blues, the chorus is the gospel, moving from the grit, the dirt, the tangible, to the hope, the prayer, the intangible. To me, that's life. Those are the things people experience and yearn for always. That's the essence, certainly of American life, but I think all human life too.” America may have to endure rather more than a verse or two more of the blues over the next years, but at least it is being guided by a man who can offer up some gospel once in a while. America's back, and the Boss with it.