Who's winning, pictures, issues and quotes - BBC News Online presents an at-a-glance guide to the US election today.
THE HEADLINE NEWS
Bill Clinton has returned to the political fray to campaign for John Kerry in Philadelphia on Monday, less than two months after having major heart surgery.
The former president said Mr Kerry was the kind of man who wanted people to "think and hope".
Earlier he told ABC's Good Morning America programme that he believed Mr Kerry could win the election, but added it was one of the most difficult results to call that he had ever seen.
On the same show, President George W Bush said he had not yet considered losing on 2 November. "I believe we're going to win and I'm campaigning as if we are going to win," he said.
Mr Clinton is set to travel to Florida for a rally on Tuesday, in a return to the campaign hailed by Democrat strategists but derided by Republican insiders who call it a sign of desperation on Mr Kerry's part.
Mr Kerry visits four states on Monday - New Hampshire, Pennsylvania, Michigan and Wisconsin - while Mr Bush rallies supporters in Colorado and Iowa.
WHO THE PAPERS BACK
The Washington Post endorsed challenger John Kerry on Sunday, but had its reservations: "We do not view a vote for Mr Kerry as a vote without risks. But the risks on the other side are well known, and the strengths Mr Kerry brings are considerable."
In the battleground state of Colorado, on the other hand, the Denver Post endorsed Mr Bush after backing Democrat Al Gore in 2000.
But like the Washington paper, it tempered its endorsement: "Just for the record, we consider both Bush and Kerry qualified to be president, and we don't think the world will come to an end if voters turn to the Democrat."
Both candidates can be pleased with what papers said in other major swing states: Three Ohio newspapers backed the president, while in Florida the Orlando Sentinel endorsed Mr Kerry - its first Democrat in 40 years.
WHO'S AHEAD
Pollsters and pundits still say the race is too close to call, with analysts at the highly respected ABC News column The Note putting the point plainly.
"You should laugh in the face of anyone who claims to know who is going to win. And thus you should stop asking us who is going to win.
We promise we don't know."
The non-partisan website Electoral-vote.com has Mr Bush on 254 votes to Mr Kerry's 253 as of Sunday, with two states - Florida and Hawaii - too close to call. A candidate needs 270 votes to win.
KEY QUOTES
I think this is really one of the most difficult elections to call that I have ever seen.
Bill Clinton discusses John Kerry's chances on ABC's Good Morning America
I'm not there yet.
George W Bush, asked if he had considered the possibility of losing, on Good Morning America
BUSH PICTURE
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Two Republican heavyweights got to grips with each other

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Both candidates delighted supporters when they were joined on the campaign trail by popular members of their parties.
George W Bush was accompanied by the man who came to personify the grit and determination of New Yorkers after the 11 September 2001 attacks.
KERRY PICTURE
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An ex-president and his would-be successor support each other

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In Philadelphia, crowds turned out not just for their candidate this year, but also for an old favourite.
John Kerry's campaign got a boost from the return to the campaign trail of the last Democrat president.