Young, skinny and a little anxious: The other side of the adored Barack Obama

When you actually see Barack Obama, it's startling how slight he is and how young he looks. I watched him arrive for a meeting in Philadelphia this week, and he had an anxious, fretful little smile, as if it were his first campaign speech. His ears stick out and his clothes hang loose. There's nothing glossy or plump about him. Most successful American politicians look well-fed on endorsements, campaign contributions and chicken dinners. He looks like a boy going to a job interview in his first suit.

Earlier in the week he had gone bowling, an attempt to make him seem like one of the guys. It hadn't worked. He did poorly - 37 points - and several balls ran into the channel beside the alley, or "gutter". In an election where the tiniest event is played and analysed endlessly on television, this was a gift to Hillary Clinton, who called for an end to gutter politics, and offered to settle the nomination in a bowling contest - her way of saying that she was the regular guy, and he was the nerdy fellow who can't even throw a bowling ball straight.

If it wasn't for the colour of his skin, the charge his opponents might make against Obama is that he is the latest in a long line of nerds chosen by the Democrats; policy wonks such as Dukakis and Gore, long on earnest proposals, short on personal appeal. That changes when he opens his mouth. In the past, most black American politicians have adopted the rhetoric and rhythms of the pulpit, voices swooping and rising, as if the larynx and the whole body were hurling themselves furiously at the topic. Barack is quieter. He doesn't sound like a preacher, but he is compelling. His speech patterns would be right for a lawyer summing up for the defence, in front of a jury allowed to react how it likes.

And react they do. They screamed and yelled and whistled and chanted. "Yes we can!" they shouted over and over. It's one of the Obama campaign slogans. Another is "Fired up! Ready to go!" Part of his schtik is to describe how he got that phrase from a little old lady early in the campaign when, tired and dejected, he had travelled to a town in South Carolina where he was met by 20 people. He'd been upstaged by the old lady chanting her slogan, and had started using it with his staff. Then he changes gear. "You see, one voice can change a room, it can change a city, it can change a state - and it can change a nation!" As the cheers grow he adopts the old trick of talking through the noise - it's almost impossible to hear him, but that's not the point. It means "what I have to say is so important, I can't even wait for you to calm down!"

There was far more raw enthusiasm than they'd shown for Hillary the previous day. Anywhere in America these days you'll see the people who love Barack love him as much as the people who hate Clinton hate her. The votes of indifferent people count as much as anyone else's, but there is no doubt who is most adored.

The speech is unabashed populism. With even the authorities now suggesting a recession is imminent, it would be hard to go any other way. He scarcely bothers to attack Hillary, and launches into John McCain, the Republican candidate presumptive. McCain has to be coupled with Bush, quite the most unpopular president for decades.

"McCain is offering the same as George Bush, putting the American dream out of reach for ordinary Americans." The administration is to blame for the crisis. "They didn't lift a finger, not until the pain being suffered in Main Street trickled up to Wall Street." He accuses McCain of wanting to occupy Iraq for 100 years - an exaggeration since McCain merely said some US troops might need to stay there.

Obama's finest hour was probably the speech last month after TV ran footage of the anti-American sermons of his pastor in Chicago, Jeremiah Wright. The speech, stripped down, can seem evasive. Wright was deeply mistaken about America, yet much of what he said was true. Black people are trapped in a cycle of continuing poverty. But so are many white people. The speech is moving and quietly emotional, thought-provoking without being provocative.

"God bless America!" he yells at the audience. Half an hour later he is in a market, dodging an importunate passer-by who wants a picture on his phone. The event is run several times on TV as if it showed him as a surly curmudgeon, avoiding the voters. To me he looked like that slightly bewildered young lad, wondering what he's let himself in for.