Obama and his opponent, John McCain, have spent the last days of the campaign criss-crossing the nation in a final mad push for the votes that will make the difference. Where they sought those votes tells the tale of both campaigns and reflects what their internal polling is showing.

So while Obama felt free to campaign in states that were all won by Bush in 2004 McCain has worked frantically to shore up his base in these same states, including his home state, Arizona, now on the toss-up list along with Florida, North Carolina, Missouri, Indiana, Georgia, Virginia, Ohio and Montana. The Obama campaign, boosted by enthusiastic volunteers, has worked assiduously at the community level across the nation, with 38per cent of voters saying they have been contacted in recent weeks.

Diehard Republicans think it's a close race that is winnable, but that possibility is not shared by many outside the McCain campaign. They argue the polls are wrong because they are based on high turnouts of young people and African-Americans for Obama.

The expectations are 65 per cent to 75 per cent of first-time voters (who now make up 13per cent of the voter population) will support Obama, and he will get about 96per cent of the black vote. Hoping these enthusiastic voters won't turn out does not seem like a viable winning strategy.

Praying that undecided voters will go for McCain at the last minute might work.

The shame is that, despite the expenditure of close to $US2billion ($A3billion at today's conversion rate) on the campaign, get-out-the vote drives, endless rallies and flurries of advertising, more than 50million eligible Americans, some eight million of them African-Americans, won't cast a vote this time round.

This year the polls are alert to the unknowns, looking for the Bradley effect, the reverse Bradley effect and the voting preferences of people with mobile phones. The best indicator is poll trends, and Obama has been consistently ahead by five to eight points, with 50per cent or more of the vote, for several weeks now.

Another important indication is coming from early voting, now available in more than 30 states. About one-third of the electorate have already cast their votes, and the preferences of this early voting group favour Obama over McCain by 53 per cent to 43 per cent.

Nor can McCain look to gain from vote splitting. Voters are evenly divided, 48per cent to 47per cent, in their preferences for the party that should control Congress if Obama is elected president; but if McCain wins, 57per cent want divided party control of Congress.

The main driver in this election is the economy, which outweighs all other issues in voters' minds. As the stockmarket lurches daily, home mortgages are foreclosed and credit dries up, the election has become a referendum on who can best manage the economy. Obama wins that referendum by a substantial margin.

John McCain is facing huge odds and almost certain defeat, let down by his campaign and a willingness to abandon his own principles for political expediency.

Barack Obama's election will bring a seismic shift in American politics and perceptions at home and abroad.

His life story, while far from typical, represents the realisation of the American dream that for many, for reasons of race, religion, opportunity and culture wars, has been severely eroded.

Obama is a leader, educated, erudite, charismatic and caring. It seems Americans have hungered for these values even as the McCain campaign and its chorus have equated them with liberalism, socialism, lack of patriotism and pop star ambitions. Obama's appeal transcends race, class and even political affiliation.

Obama has run a campaign noted for its organisation, cohesion and planning. He has demonstrated his ability to gather the best and brightest around him, to listen, to reach out and to respond when action is needed. He has the ability to make the US feel good about itself, to restore its international respect and standing, and to heal the scars left by eight years of Bush and the neocons, the Iraq War, an economic crisis and his opponent's divisive campaign.

Dr Russell is the Menzies Foundation fellow at the Menzies Centre for Health Policy, University of Sydney/Australian National University and a research associate of the US Studies Centre, University of Sydney.