As someone who has been both a follower of and a participant in political campaigns for more than 30 years, I remain an election groupie. So a two-week American book tour has given me a once-in-a-lifetime opportunity to feed my addiction.

It was an exhilarating, enlightening experience. There is nothing more exciting than the feeling that a country is on the move. For the sense of anticipation of change was almost palpable.

I arrived back last week, before, of course, the crucial last days of campaigning. So it's possible still that the electorate will confound the pollsters and experts on Tuesday.

But the mood seemed, to an observer such as myself, very different from four years ago, when I also found myself in the United States. Then I was struck by how many people, even in Democratic strongholds such as New York, told me that they wanted to give President Bush a second term. This was when the polls and many experts were still suggesting a modest victory for John Kerry, his Democratic challenger.

On this visit, however, it felt very different. Maria Shriver, the wife of Arnold Schwarzenegger, told me that Barack Obama posters out-numbered John McCain's two to one in the Governor's mansion, with mother and daughter out-gunning Arnie.

The increasingly loud complaints I heard from Republicans about media bias and the unfairness of the Democrats' fundraising success also made an impression. The Democrats instead held the silent fear that this election would again be snatched from their grasp at the last minute.

Even in staunchly Republican Texas, there was a sense that the country was facing a political upheaval, if not in the state itself then in the US as a whole. They didn't like it, but felt powerless to stop it happening.

From my own experience, and in particular my walk-on role in the 1997 election campaign, I know that the one place this feeling won't have taken a grip is within the Obama campaign team. It's not just that every politician understands that taking the electorate for granted is the quickest way to lose. It is also that the more favourable the polls, the more they will want to discount them.

In 1997, during a six-week campaign - both the longest and the quickest six weeks of my life - the polls consistently gave Labour a big lead over the Tories. But we could never believe what we were hearing.

After the election that was lost in 1992 and a confidence-sapping 18 years in the political wilderness, no one on the Labour campaign team believed the election was in the bag. Those of us inside the leader's campaign bus were probably the most immune to the mood of change that proved to be sweeping the country.

There was, in fact, a tremendous desire to minimise the poll leads. No one wants to be the front-runner who blows what was supposed to be an unlosable election. Even on election night, when the exit polls and first victories pointed to a landslide victory, the mood was still very nervous. So I have no doubt that both presidential candidates, while aware of the polls, will be focused on the gruelling day-to-day task of winning and keeping the voters' trust.

What is also striking when viewed from America is that, whatever the similarities between elections, the internet has made this presidential race very different from any before. In 2001 we thought the Labour Party was very cool when it sent out text alerts to young Labour voters. The extraordinary use of the web and mobile technology - particularly by Obama's campaign - is as different, as one US expert has put it, from these clumsy first efforts as the Wright brothers' first flight was from Neil Armstrong landing on the Moon. And all in the space of a handful of years.

During the long nomination battle, Obama proved himself the master of the web, reaching out to a whole new audience, mainly youthful and often disconnected from old-style politics. John McCain's campaign has had to struggle to keep up.

It has led almost to two separate campaigns - one in the actual world and one in the virtual. But the web's influence goes far beyond the official campaigns. It has provided new opportunities for voter participation at a time when the old party system has left many feeling alienated. It is helping to give democracy back to the people.

There's no doubt that Obama has so far been the big winner from this revolution, connecting afresh with millions who had felt that politics was irrelevant to their lives. But one of the questions to be answered this week is how real this new virtual army of supporters is. The number of these cyberspace enthusiasts who are willing to take part in the slightly less cool activity of visiting a polling booth might help to decide the contest.

In 1997, I only believed the scale of the victory when I saw that Labour had won Crosby, where I had grown up, for the first time. As for the candidate himself, he never got the chance to relish what he had achieved. By the time we got to bed at 6am the next day, the sober realities of actually putting the mandate into practice had already sunk in and he was focused on forming a new government and the challenges of the days and weeks ahead.

The American system, at least, allows the president-elect a couple of months to prepare for what is to follow. It should also mean that Michelle Obama or Cindy McCain, unlike me, will have the time and sense to get dressed and brush her hair before opening the door - something I neglected to remember.

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