As Barack Obama and John McCain hopscotched across time zones covering more than a dozen battlegrounds in the final days of the election, both men found themselves back where it all began for them.

Mr Obama went to Iowa, an almost all-white state that became his base camp in what he calls a “steep climb” towards becoming America’s first black president. “On the day of the Iowa caucus, my faith in the American people was vindicated and what you started here in Iowa has swept the nation,” he told a rally in Des Moines on Friday.

Mr McCain returned to New Hampshire wearing his “lucky red sweater”, where he trails Mr Obama by double digits — but has sentimental memories of his comeback victory in the primary. “I’ve come to the people of New Hampshire, Republicans, independents, Democrats, libertarians, vegetarians, to ask again, to let me go on one more mission,” he told a town hall meeting in Peterborough on Sunday.

Since those states kicked off the nomination process in January, both candidates have flown tens of thousands of miles over an electoral landscape in upheaval from fast-flowing changes in the make-up of voters, economic turmoil, as well as the seismic racial and generational forces unleashed by Mr Obama.

Yesterday they were back on their planes one more time. Mr McCain embarked on a seven-state, 18-hour helter-skelter tour across America to Tennessee, northeast to Pennsylvania, then west to Indiana, New Mexico, Nevada and finally home to Arizona, where he will hold a midnight rally on the courthouse steps of the old territorial capital of Prescott.

Mr Obama trawled for votes up the East Coast through Florida, North Carolina and Virginia before heading to Chicago for what he hopes will be a vast election night celebration at Grant Park.

The campaigns have spent months mining deep into the fault lines dividing American politics: race, class, gender, age, religion and region. But polls suggest it is the Democrats who have struck gold. And this year they have not had to stay within the narrow seams of traditional swing states such as Florida, Ohio and Missouri.

Mr Obama is opening up new frontiers in the western Rocky Mountains, through Colorado, Nevada, New Mexico. Much of this is down to the arrival of Hispanic voters — who favour Mr Obama by two to one — suburban migrants pushing these states away from the rugged individualism that once made them Republican strongholds.

Mr Obama is also driving deep into the South, where the Democrats are competitive in states for the first time since whites fled to the Republican camp during the civil rights era.

Polls show that Virginia, which has not for voted for a Democratic presidential candidate in 44 years, is leaning towards him. North Carolina, Republican since the time of Jimmy Carter, is seen as a toss-up. Georgia, won by President Bush four years ago with a 16 per cent margin, is now regarded as a long-shot Democratic gain.

A population shift towards liberal suburbs and a surge in voter registration among blacks — whose support for Mr Obama is almost monolithic — is helping Democrats to recapture at least some of the South.

There has been a similar increase in registration for young people, the same group who helped to propel Mr Obama over the finishing line in the Iowa caucuses, with first-time voters backing him over Mr McCain by almost two to one.

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