JACKSONVILLE (Florida) - BARACK Obama stood on the threshold of history on Monday as polls gave the Democrat a solid lead over John McCain on the last day of campaigning for the most dramatic US presidential vote in a generation.

But Mr McCain, who has no room for error in the tense battle for a handful of toss-up states, vowed to confound the pollsters and wrench victory from the African-American's grasp on Tuesday.

Obama leads in 6 of 8 key states WASHINGTON - DEMOCRAT Barack Obama leads Republican John McCain in six of eight key battleground states one day before the US presidential election, including the big prizes of Ohio and Florida, according to a series of Reuters/Zogby polls released on Monday. Mr Obama holds a 7-point edge over Mr McCain among likely US voters in a separate Reuters/C-SPAN/Zogby national tracking poll, up 1 percentage point from Sunday. The telephone poll has a margin of error of 2.9 percentage points. -- REUTERS

The 47-year-old Democrat stressed the historic nature of his quest to be America's first black president, striking an optimistic tone as fresh polls gave him a wide lead and heaped further pressure on Mr McCain.

'This is a defining moment in our history,' Mr Obama wrote in an article published in The Wall Street Journal.

'Tomorrow, I ask you to write our nation's next great chapter... If you give me your vote, we won't just win this election - together, we will change this country and change the world.'

Mr McCain, a 72-year-old former prisoner of war in Vietnam, was defiant. 'My opponent is measuring the drapes at the White House,' he said, as he wrapped up a frenzied day of campaigning with a midnight rally in Miami.

'The Mac is back! And we're going to win this election,' he added.

The Republican was to dash through at least seven states on the marathon campaign's final day. Mr Obama was to blitz through Florida, North Carolina and Virginia bidding to storm Republican bastions and turn them over to his side.

Rallying supporters in Ohio on Sunday, Obama said his rival's policies would extend President George W. Bush's legacy of financial crisis and 'war without end' in Iraq.

In his own Wall Street Journal article, Mr McCain shot back at his rival on the economy. 'Senator Obama wants to raise taxes and restrict trade,' he charged. 'The last time America did that in a bad economy it led to the Great Depression.'

The final pre-election poll of Gallup-USA Today published on Monday gave Obama a yawning lead of 11 points - 55 per cent to 44 for McCain.

'It would take an improbable last-minute shift in voter preferences, or a huge Republican advantage in election day turnout, for McCain to improve enough upon his predicted share of the vote... to overcome his deficit to Obama,' the pollster said.

A new Wall Street Journal-NBC News poll put Mr Obama ahead on 51 per cent to 43. CNN's latest poll on Sunday had Mr Obama with a 53-46 per cent edge, a Washington Post-ABC News poll gave him 54 per cent to 43, and Rasmussen said he was at 51 per cent to Mr McCain's 46.

Mr Obama also leads by slimmer margins in the battleground states where the election will be won and lost, including in states such as Virginia and North Carolina that have not backed a Democratic hopeful in decades.

A Quinnipiac University poll examining the three states with the largest number of electoral votes - Ohio, Pennsylvania and Florida - found Obama's lead had narrowed slightly to 51-42 in Ohio and 53-41 in Pennsylvania, while Florida was too close to call.

A separate poll by The Washington Post and ABC said that in six states considered to be up for grabs, support was roughly split with 51 per cent support for Mr Obama and 47 for Mr McCain.

And a CNN/Opinion Research Corporation (ORC) survey released on Monday said that 59 per cent of voters feel Obama can bring 'change', while about the same number say Mr McCain cannot, the network reported on its website.

Mr McCain's whistlestop tour on Monday was expected to include campaign stops in Florida, Virginia, Pennsylvania, Tennessee, Indiana, New Mexico and Nevada before he was to head home to Arizona.

Another CNN/ORC poll meanwhile suggested that Mr McCain's running mate, Sarah Palin, may be dragging down the Republican's chances. The news network said Mr McCain had 48 per cent support, but backing for Mr McCain and Mrs Palin as a unit was lower, at 46 per cent.

The battle has narrowed to states that have been reliably Republican in recent elections, as Mr Obama's deep-pocketed campaign expands to places where the Democrats have not won in years.

Victories in Colorado and Nevada out west, on top of his lock on Iowa in the US heartland, would let Mr Obama clinch the White House without even winning the states that decided the past two elections: Ohio and Florida.

To win, a candidate needs to gain 270 votes in the Electoral College that formally selects the next president.

States are apportioned electoral votes according to the size of their population and in most cases the winner of a state's popular vote gets all its electoral ones. -- AFP