President Barack Obama has framed the election as a question of trust and warned American voters they cannot rely on his 'reckless' and elusive Republican foe Mitt Romney.
The president's beseeching tone and the new urgency in his appeals reflect the fact that in three debates he failed to sink Romney's campaign and signs that it is the Republican, not Obama, who has momentum in the tight race.
'I do what I say, you've seen me,' an impassioned Obama told a big crowd in Florida, hours after his final debate clash with Romney effectively fired the starting gun on a frenzied two-week sprint in a tied White House race.
Romney flew west after the debate, riding a tide of optimism in his campaign and presenting himself as a voice of change, as he sought to peel away the states of Nevada and Colorado.
'His is a status quo candidacy. His is a message of going forward with the same policies of the last four years. And that's why his campaign is slipping. And that's why ours is gaining so much steam,' Romney said.
To counter such claims, Obama rolled out a book detailing his second term agenda and unveiled a new ad laying out his closing argument, telling Americans it was an honour to be their president and asking for four more years.
But Romney's spokesman Kevin Madden mocked the publication as a 'glossy panic button' saying that the trio of debates had reshaped the White House race in the Republican's favour and that Obama was running out of time.
Obama sought to nail Romney as a political shape shifter after his opponent in the November 6 election presented himself as a sober man of peace in their final debate on Monday, toning down previously hawkish foreign policy positions.
He diagnosed the Republican as suffering from 'stage three Romnesia,' accusing him of misrepresenting and simply forgetting a litany of past positions in a win-at-all costs effort to seize the White House.
'We are accustomed to seeing politicians change their positions from four years ago, we are not accustomed to seeing politicians change their positions from four days ago,' Obama told a rowdy Florida crowd.
'You can choose the foreign policy that's reckless and wrong, or you can choose one that is steady and strong,' the president said, before heading to Ohio, the perennial swing state that may decide the election.
'This is about trust. There is no more serious issue in a presidential campaign than trust. The person who leads this country, you have got to have some confidence that he or she means what he or she says.'
'You know me, you can trust that I say what I mean and I mean what I say.
Madden mocked the president's 'Romnesia' applause line, painting it as evidence that the Democratic incumbent's campaign was out of ideas.
'The fact that the president feels the need to play Scrabble with his opponent's last name is really telling about the state of their campaign, and really telling about the state of the President's closing argument.'
Later, in Dayton, Ohio, where one-in-eight jobs relies on the auto industry, he lacerated Romney over his opposition to an industry bailout he authorised in 2009.
'I bet on American workers. I bet on American manufacturing. I would do it again because that bet has paid off for Ohio and for America in a big way,' said Obama, appearing before 9,500 people with Vice President Joe Biden.
Obama's verve on the stump on Tuesday was a stark contrast to his muted arguments earlier in the campaign, perhaps because time is running out to make his case to the American people.
The question now for Obama: is it too late? Polls have shown movement towards Romney following a listless first debate performance by the president on October 3 that appears to have reset the race in his opponent's favour.
Romney led an average of national polls by 0.7 per cent on Tuesday, but Obama still held small leads in states including Ohio, Iowa, Nevada, Wisconsin and New Hampshire that could make him president for a second time.
But the president now has little room for any erosion of his position with only two weeks left, though he may be helped by the fact that some battleground states are already holding early voting.