White House front-runner Barack Obama duelled with John McCain on the penultimate day of the epic 2008 campaign, presenting a tableau of his loving family and vowing to change America.

On the home stretch before Tuesday's election, the Democrat bidding to be America's first black president appeared before 80 000 supporters with his wife Michelle and their two daughters aged seven and 10.

But McCain fought for a comeback win in Pennsylvania — which went Democratic in 2004 and which he must win to stand a chance of victory — as the state Republican Party ran an ad about Obama's fiery former pastor Jeremiah Wright.

Obama and his family were introduced by a rousing set from fabled rocker Bruce Springsteen in Cleveland, who brought many in the vast crowd to tears with "The Rising," which is played before all Obama rallies.

"A rising is coming," Obama said after Springsteen exclaimed to deafening cheers: "I want my country back, I want my dream back, I want my America back!"

Changing America

McCain, following his own two-day bus odyssey around rust-belt Ohio, was also stepping up the pace with his first midnight rally of the campaign, in Florida, following events in Pennsylvania and New Hampshire.

"We are two days away from changing America, and it's going to start right here in the great state of Ohio," said the 47-year-old Obama, whose rival McCain, at 72, would be the oldest president elected to a first term.

The Democrat's campaign has not made the age difference an explicit issue of the election, but the contrast was implicit as his young family rejoined him on the campaign trail at rallies in western states on Sunday and in Ohio.

Obama again hammered McCain on the stricken US economy, and said his policies would extend President George W. Bush's economic and foreign policy legacy. His wife meanwhile exhorted supporters to vote early or turn out en masse on Tuesday.

"There's this beautiful thing about my husband, he thinks he can do everything," Michelle Obama told an earlier rally attended by more than 60 000 people in Columbus, Ohio.

But she stressed: "Barack Obama needs you for the next two days. He's going to need you for the next four years and eight years."

'Everything looks a little better'

The Democratic nominee seemed buoyed by the presence of his family.

"Everything looks a little better. Crowds seem to grow and everybody's got a smile on their face," he said. "You start thinking that maybe we might be able to win an election on November 4."

Obama has been criss-crossing battleground states that backed Bush last time, and the latest polls make him the hot favorite.

But McCain said the polls had been wrong before, and would be wrong again come Tuesday.

"My friends — the Mac is Back, and we're going to win," he roared in Pennsylvania, a rust-belt state where polls favor Obama and which he must win to have any chance of getting the 270 electoral votes needed for victory.

The Pennsylvania Republican Party meanwhile ran and ad about Wright, who pitched Obama's campaign into crisis earlier this year when video clips of his shriek "God Damn America" in a sermon surfaced.

"Barack Obama: he chose as his pastor a man who blamed the US for the 9/11 attacks. Does that sound like someone who should be president?" the ad said.

One last mission?

Later the Arizona senator returned to New Hampshire, where he won the Republican primary in 2000 and earlier this year.

"I come tonight to the independents, Republicans, Democrats, Libertarians, vegetarians, asking you to let me go on one more mission," he said, in one of his signature town hall meetings in the northeastern state.

In the US presidential Electoral College, states are apportioned votes based on their population, ranging from giant California with 55 to the least populous states such as Alaska, Montana and Vermont with just three.

Gallup laid bare the challenge that McCain faces, with its tracking poll on Sunday giving Obama a lead of up to 11 points depending on the survey model used. Among "traditional likely voters," Obama was up 51 percent to 43.

A Washington Post-ABC News poll gave Obama a 53-44 percent lead, and Rasmussen said the Democrat was on 51 percent to McCain's 46.

McCain's campaign manager Rick Davis, however, said the polls were skewing the true perception of the race.

"There is no doubt that John McCain is increasing his margins in almost every state in the country right now, and I think what we're in for is a slam-bang finish," he said on Fox News on Sunday.

The presidential campaign has narrowed down to states that have been reliably Republican in recent elections, or in the case of Virginia, Indiana and North Carolina, that have not voted for a Democratic hopeful in decades.

AFP