Barack Obama hit back strongly against criticism of his economic plan today as polls showed the race for the White House was tightening with just 12 days to go.
Mr Obama and John McCain were virtually tied in an AP-GfK poll which had the Democrat leading by more than seven points three weeks ago.
But other polls offered conflicting snapshots, with one by Reuters/C-SPAN/Zogby giving Mr Obama a strong 12-point lead.
The Obama campaign was taking no chances as the 47-year-old Illinois senator emphasised the stakes at a rally in Indianapolis, Indiana, before leaving to visit his gravely ill grandmother in Hawaii.
He said Mr McCain’s “fundamental economics” was “just another name for Wall Street first, Main Street last”.
“That’s the kind of economic philosophy we’ve had for the past 10 years and that’s fundamentally wrong,” he said.
“We’ve tried it John McCain’s way, we’ve tried it George Bush’s way, and we’re here to say: ’enough is enough’.
“We can’t afford four more years of their ’fundamental economics’. That’s why I’m running for president of the United States, to get economics that works for you.”
He added that “say anything, do anything” politics was taking over the campaign in its final days, with “careless, outrageous comments” by his opponents which were “aimed at stopping change”.
Earlier, Mr Obama told the US TV network CBS that he could not imagine running the kind of negative campaign he was facing from Mr McCain.
He said talk of socialism and of “palling around with terrorists”, as the McCain campaign has claimed, represented “the kinds of stuff that I can’t imagine saying about an opponent of mine”.
Such negative campaigning is also thought to be disliked by the majority of voters.
Over the past four days, 21 national polls have been taken, and Mr Obama has led in all of them.
He led by five or more points in 17 of them, with five of these giving him a double-digit lead.
The last time Mr McCain led in the polls was in early September, when he had a slim lead in four polls of between one and four points.
However, Obama campaign aides said they would not be surprised if polls tightened further before election day on November 4.
Mr Obama, who would become the first African-American US president if elected, also faces the unknown consequences of the so-called Bradley Effect in the 2008 election.
The phenomenon is used by some political pundits to explain why polls could overestimate support for an African-American candidate.
The theory claims some white voters misrepresent their intentions and tell pollsters they will vote for the black candidate due to social pressure but then vote for the white man as they cast their secret ballot.
It earned its name when polls suggested Tom Bradley, the black Democratic former mayor of Los Angeles, would win the governorship of California by a wide margin in 1982, but he went on to lose by more than 100,000 votes.
Opinions are split as to whether the effect will be seen this year.
Back on the campaign trail, Mr McCain was targeting blue collar workers in Florida with a “Straight Talk Express” bus tour.
The Sunshine State, with its large prize of 27 of the 270 electoral college votes needed to become president, is a must-win for the McCain campaign.
But the latest average of polls by RealClearPolitics.com show a virtual dead heat in the state, despite it voting for Republican George Bush in both 2000 and 2004.
From Ormond Beach on the Atlantic Coast to Sarasota on the Gulf Coast, Mr McCain was traversing the state with stops focused on criticising his rival’s tax plans in a series of “Joe the Plumber” events.
Joe Wurzelbacher, of Holland, Ohio, became a thematic figure in Mr McCain’s campaign after he was filmed questioning Mr Obama over whether the Democrat’s tax plan would prevent him from buying the two-man plumbing shop where he works.
Mr Wurzelbacher subsequently revealed he did not make enough money to reach the US$250,000 (€195,061) threshold, and several analyses suggested he would pay fewer taxes under Mr Obama’s tax proposal than Mr McCain’s.
But the Republicans have embraced “Joe the Plumber” as an icon for their campaign in recent days.
Speaking in Ormond Beach, Mr McCain said small business owners across America had the same dream as Joe the Plumber.
“Obama wants spread the wealth around,” the 72-year-old Arizona senator said.
“That means fewer jobs at their businesses and fewer jobs here in Florida.”
He added that Mr Obama was now changing his tax plan “because the American people have learned the truth about it and they didn’t like it”.
“It’s another example that he’ll say anything to get elected,” he said.
The McCain campaign also released an advert showing “Americans who submitted their homemade videos to the campaign telling their stories and how they are like ’Joe the Plumber’.”
“Like Joe in Ohio, people from across the country do not want to see their taxes increase as Barack Obama proposes,” a McCain campaign spokesman said.
“They don’t want a president who will ’spread the wealth around’ instead of creating new wealth and new opportunity.
“They don’t want a president who sees economic success, expansion and job creation as an excuse to increase taxes.
“They don’t want a president who will place a tax on the American dream.”
From Florida, Mr McCain will fly to Denver for appearances in Colorado tomorrow.
Mr Obama is on his way to Hawaii to be with his gravely ill 85-year-old grandmother, Madelyn Payne Dunham.
Leaving the campaign trail less than two weeks before the election is a highly unusual move, but most US political pundits agreed Mr Obama had little choice. He will return to campaigning in Nevada on Saturday.