Barack Obama and Mitt Romney will this week throw themselves into frantic, almost non-stop tours of the battlefield states that will help decide what is shaping up to be one of the most closely contested elections in recent US history.
In a sign of the intensity of the campaign in the final fortnight, after Monday's third and final presidential debate, Obama is to travel to six swing states and his hometown, Chicago, in 48 hours. The president, who normally returns to Washington overnight, is to sleep aboard Air Force One to save time for campaigning and will also make election calls while the plane is in the air.
A new Wall Street Journal/NBC poll shows that after trailing Obama all year, Romney is now tied with him on 47% of the likely vote. The last WSJ/NBC poll, taken before the first presidential debate in which Romney dominated the president, had Obama ahead by 49% to 46%.
One of Obama's chief advisers, David Axelrod, expressed scepticism about the polls when he appeared on NBC on Sunday, pointing to huge variations in findings.
"I do think that this is going to be a very close race, and we've said that consistently," he said. "We feel good about where we are. We feel we're even or ahead in these battleground states."
An election that had seemed listless is entering its last phase with re-energised Republicans finally believing that their candidate might make it to the White House and Democrats panicking at the thought that Obama might be slung out of office after a single term.
Tens of thousands of volunteers, many of whom had been disinterested for much of the year, turned up at campaign offices over the weekend, conscious at last of what is at stake on 6 November.
The two candidates go into Monday's debate in Boca Raton, Florida, with Romney having won with a knock-out in the first in Denver and Obama winning on points in the second in Hempstead, New York. The 90-minute Boca Raton debate will be devoted to foreign affairs.
As president, with daily access to briefings on foreign affairs and security, Obama goes into the final debate as favourite, not least because it gives him another chance to remind voters that Osama bin Laden was killed on his watch.
But Romney, after two botched attempts to force Obama onto the defensive over Libya, will try again over the assault on the US consulate in Benghazi that left the ambassador and three other Americans dead.
The US response to the stand-off with Iran over its nuclear programme is almost certain to be debated. The New York Times reported on Sunday that the Obama administration had achieved a diplomatic breakthrough with an agreement in principle to one-to-one talks with Tehran after the election. The Iranian government has long argued for one-to-one negotiations rather than the international coalition of the US, Britain, France, Russia, China and Germany.
The White House denied there had been an agreement, but said it was open in principle to such negotations.
In a sign of how engaged voters have become, an estimated 65.5 million people watched the second debate, one in which the figures normally drop off substantially. It was only marginally down on the first one, which was watched by 67 million people, and well up on 2008 viewing figures. Even amid the excitement then at the prospect of the first African-American president, the three debates averaged audiences of around 57 million.
Obama spent the weekend in debate rehearsal at Camp David, while Romney held his last fundraising event at a donor's home in Palm Beach, Florida, freeing himself for debate preparation at a hotel in Boca Raton and the campaign sprints that will follow.
With the debate over, Obama will on Wednesday embark on a two-day campaign blitz of six swing states: Iowa, Colorado, Florida, Nevada, Virginia and Ohio. He will also drop into his hometown Chicago to cast his ballot early.
"As the president crisscrosses the nation, he will spend time on Air Force One calling undecided voters, rallying national team leaders and volunteers and continuously engaging with Americans," his campaign said in a statement.
Romney will head for two days of campaigning in Nevada, Colorado and Ohio on Tuesday.
The Republican campaign has been underway since at least the Ames straw poll in Iowa in summer last year, a traditional early test for candidates seeking the party's nomination. The Republican nomination race produced lots of headlines, from allegations of sexual harassment by Herman Cain to Newt Gingrich's proposals for a colony on the moon, but the election failed to capture the public imagination in the same way as 2008.
But Romney's victory in the Denver debate and the subsequent tightening in the polls has changed all that.
Both campaigns having raised close to $1bn (£625m), meaning that the candidates go into the final fortnight with funds to saturate ad markets in every swing state. It is the costliest election in US history.
An analysis by the Politico website suggested the Obama campaign had raised $969m in funding and the Romney campaign $919m. Both will be asking for more donations over the final two weeks.
Filings by the Republicans over the weekend to the federal election commission, as required by law, showed Romney and the Republican party ending September with $183m in hand, compared with $149m for Obama and the Democrats. The Obama campaign spent heavily over the summer in a pre-emptive strike while Romney has been hoarding cash for a final ad blitz.
As alarming for Democrats as the WSJ/NBC poll is one by Public Policy Polling in Ohio, the bastion on which Obama rests his hopes if the east coast swing states - Florida, North Carolina, Virginia and New Hampshire - fall to Romney. PPP has Obama on 49% and Romney on 48% in what is a predominantly working-class state in America's industrial heartland.
guardian.co.uk © Guardian News and Media Limited 2010