Obama: Can he prove he's a regular guy?

Since he declared himself the winner of the primaries marathon two months ago; since he stood before a crowd of 200,000 in Berlin, Barack Obama has changed. Indeed, in this university gymnasium in Missouri his head does actually seem bigger.

It is a change that has not escaped John McCain's notice. Unconcerned by charges that he is turning too nasty too soon, he has been ripping into Obama for being arrogant and out of touch. I, though, am talking about physical appearance. Maybe it is the summer suits and shirt-sleeves, but Obama has surely lost weight. Hence the head that seems larger. Is it the narcotic of approaching power that is stopping him eating? Or is it fear of losing?

These are delicate days for the senator from Illinois. He admitted on his way home from Europe there was the risk of "flying too close to the sun". So call this his "Back to Earth Tour", in rural Missouri and in Iowa. The crowds are not huge, though still adoring. This week, he is not preaching from mountain tops. He is holding babies in the rain and serving burgers in a pigeon-pooped park shelter.

Yet, Obama is not, as he would like, quite in charge of his own narrative or image. The missiles from Camp McCain are flying thick now, almost as if it were late October, not the start of August. There was the arrogance pitch and then the TV ads about celebrity, likening him to, of all people, Paris Hilton. Thereafter came the toxic suggestion that Obama (not McCain) was inserting race into the campaign mix.

Even at close proximity, it is hard to divine Obama's real state of mind amid these assaults. Unlike McCain, he doesn't feel much need for personal interaction with the journalists who travel with him. A special correspondent from Newsweek on his plane has asked for a little "face-time" with the candidate. She has been told to expect 30 seconds at most. Is that a symptom of cockiness?

There is a general demeanour of confidence about him. He is unfailingly deferential with people older than him. With contemporaries he is tactile – hands on shoulder – while with youngsters he can joke around. "There's a lot of carbs there," he quips, handing a burger to a teenage girl at the park barbecue in Union, Missouri. (Union and Rolla are heavily Republican, another reason Obama is back to earth.) Few see it, but as Obama steps from behind curtains into the cacophony of cheers in the gym in Rolla, he does a skip and a jump as if a featherweight prize fighter coming into the ring, sure of victory.

On policy, there are signs of sureness too. On Thursday, in Cedar Rapids, Iowa, Obama is trying to make energy policy the theme of the day, excoriating McCain's call for more offshore drilling for oil. He says new oil finds will not lower petrol prices for 10 years at least and that the big oil companies have 68 million acres of government-granted leases they are not using. But many of the faces before him look a bit blank. How much easier to say as McCain does: let's go get more of our own oil.

It surely helps that Obama is met everywhere by such love. And it's not just young, college-educated love. Tony Viessman, 74, a retired police officer, holds a banner outside the Rolla event proclaiming "Rednecks for Obama". "He is brilliant," he says. "And he is not an elitist, though he has the education to be." Helping clear up after the Union barbecue is Barbara Selter, 72. "It's the proudest moment I have had for a very long time, something that happens once in a lifetime," she says. "I feel that John Kennedy is right here."

But if Obama likes to pretend he is above the day-to-day fray, he is not. At times, he might even be getting ratty. "Is that the best you can come up with?" Obama tartly asks in Cedar Rapids, responding to McCain's Paris Hilton TV spot. And we go nowhere without Obama making this appeal: don't let the other side scare you about me. The Republicans, he warns, are talking about his "funny name" and how he "doesn't look like all those other presidents on the dollar bills". It is a cute line that gets laughter. But it also draws the admonition from McCain that Obama is introducing the race card.

More and more, this campaign looks like a referendum on Obama and much less about McCain. Are voters ready for him? Do they trust him? Does it matter that he is black? Whether he wins or loses may depend on who has control of the Obama story – him or McCain. And who the voters are listening to.

The reporters who travel with Obama – and who drive most of what makes the evening news about him – can't help here because they are never allowed out of his bubble. They don't know what voters here in Missouri or in Cedar Rapids are thinking. Has McCain hit his stride or has he gone too far with the race-card charge and the Paris Hilton stunt? They can't talk, for instance, to Chuck Pederson, 53, a government worker in Rolla who wears a "NoBama" T-shirt, has "Drill Now, Drill Here!" daubed on his truck and who flatly states that Obama has refused to debate McCain except for one time, on Labour Day, a national holiday. Which isn't true. Nor can they find Chuck Mayes, 28, a Missouri construction worker. He would never back Obama. "The first reason is his name; the second is he wasn't born here," he says. First lesson: the falsehoods about Obama are still out there and those who don't like him won't hear any different. (Obama was born in Hawaii, which may not be "here" but surely is America.)

Yet, as the Obama plane climbs out of Cedar Rapids, a possibly surprising consensus emerges at the bar at the Knights of Columbus – a Catholic charitable club that still only accepts men as members – on the edge of town. At one end, Rich Steepleton reckons these latest McCain attacks about Obama being big-headed are "all talk". He is minded to pay no attention at all. At the other, Tom Fagan wants a foreign reporter to know that, compared "to a few short years ago", America has "opened up" on issues like race, and the blackness of Obama won't matter in November. This is no college canteen, yet – every man's hand on a cold beer at lunchtime – they are agreed: it will be close in November, but Obama will win.