WASHINGTON -- President Barack Obama and Republican rival Mitt Romney scurried through decisive swing states Sunday issuing promises of better days to come while castigating their opponent, cramming as much campaigning as possible before Tuesday's election ends an extraordinarily negative race.
Nationwide polls show the men locked in one of the closest presidential races in recent American history. But a majority of polls in the battleground states -- especially in the Midwestern states of Iowa, Wisconsin and Ohio -- show Obama with a slight advantage, giving him an easier path to the 270 electoral votes needed for victory. No Republican has won the White House without carrying Ohio.
Under the U.S. system, the winner is not determined by the nationwide popular vote but in state-by-state contests, making "battleground" states that are neither consistently Republican nor Democratic extremely important in such a tight race. Romney and Obama are actually competing to win at least 270 electoral votes. The electoral votes are apportioned to states based on a mix of population and representation in Congress.
That raises the possibility of a replay of the 2000 election when Republican George W. Bush won the presidency with an electoral vote majority, while Democrat Al Gore had a narrow lead in the nationwide popular vote.
The race was so close that the final national NBC/Wall Street Journal Poll, released on Sunday, showed Obama getting the support of 48 per cent of likely voters, with Romney receiving 47 per cent. The poll had a margin of error of 2.55 percentage points.
The final national poll from the Pew Research Center found Obama with a three-point edge over Romney, 48 per cent to 45 per cent among likely voters, an improved showing that indicates the president may have benefited from his handling of the response to Superstorm Sandy. The Pew poll had a margin of error of 2.2 percentage points.
If the election were held now, an Associated Press analysis found that Obama would be all but assured of 249 electoral votes, by carrying 20 states that are solidly Democratic or leaning his way -- Iowa, Nevada and Pennsylvania among them -- and the District of Columbia. Romney would lay claim to 206, from probable victories in 24 states that are strong Republican turf or tilt toward the Republicans, including North Carolina.
Up for grabs are 83 electoral votes spread across Colorado, Florida, Ohio, New Hampshire, Virginia and Wisconsin. Of those, Republicans and Democrats alike say Obama seems in slightly better shape than Romney in Ohio and Wisconsin, while Romney appears to be performing slightly better than Obama or has pulled even in Florida and Virginia.
In perhaps the most interesting late-campaign development and with Obama sustaining his lead in Ohio, a virtual must-win for Romney, the Republican has opened a surprise, last-minute gambit in next-door Pennsylvania. The state has voted Democratic in the last five presidential elections and has long been counted in the Obama column. Romney made his first visit to the state of the fall campaign on Sunday, taking along running mate Rep. Paul Ryan.
The theme from the movie "Rocky" blared from the loudspeakers as he stepped to the podium in Morrisville, a Philadelphia suburb. "The people of America understand we're taking back the White House because we're going to win Pennsylvania," Romney told a large crowd that had been waiting for hours on a cold night.
Obama's campaign said Romney's move in Pennsylvania showed the Republican's desperation and was linked to his diminished chances in Ohio. The Obama campaign quickly bought advertising time in the state to counter a big ad push by Romney. And the Obama campaign announced that former President Bill Clinton -- Obama's most powerful surrogate -- would make four campaign stops in Pennsylvania on Monday.
Romney, who described himself as "severely conservative" during the Republican primary campaign, has shifted sharply in recent weeks to appeal to the political centre and highlights what he says was his bipartisan record as governor of Democratic-leaning Massachusetts.
Making his closing case to voters at his first stop Sunday in Des Moines, Iowa, Romney pledged, if elected, to work with Democrats to restore the American dream and bring the economy roaring back to life.
"We're Americans. We can do anything," Romney said. "The only thing that stands between us and some of the best years we can imagine is a lack of leadership -- and that's why we have elections."
In heavily Democratic Cleveland, Ohio, in the afternoon, Romney slammed Obama for what he termed the president's failure to end the partisan gridlock that has brought Washington to a virtual legislative impasse and for breaking his promises to vastly improve the economy while cutting the national debt.
"Talk is cheap," Romney said in the Lake Erie industrial city. "But let's look at the record." He went on to lash the president for what Republicans claim are a series of broken Obama promises on both the economy and changing the political climate in the country.
Romney was to close the day with a rally in Newport News, Virginia.
Obama had New Hampshire, Florida, Ohio and Colorado in his sights for the day, and, judging from the polls, a slight wind at his back.
In New Hampshire, Obama began the day saying he, too, wants to work across party lines, but said he won't give up priorities such as college financial aid or the health care law he pushed through Congress.
"That's not a price I'm willing to pay," he said, a reference to Romney's frequent pledge to dismantle the health care reform law that Republicans deride as "Obamacare."
The two rivals and their running mates flew from state to state as the last of an estimated 1 million campaign commercials were airing in a costly attempt to influence a diminishing pool of undecided voters.
About 30 million people have already cast ballots in 34 states and the District of Columbia, although none will be counted until Election Day on Tuesday.
Nearly 4 million of them were deposited by Floridians, and Democrats cited unprecedented demand for pre-election day voting as they filed a lawsuit demanding an extension of available time.
Obama and Romney disagree sharply about the approach the nation should take to the slow-growth economy and high unemployment, and the differences have helped define the campaign. Most notably, Romney wants to extend tax cuts that are due to expire without exception, while Obama wants to allow them to expire on incomes over $250,000.
At the same time, polls show bipartisanship is popular, in the abstract, at least, which accounts for the emphasis the candidates are placing in the race's final days on working across political aisles.
Romney frequently cites his ability to work with the Democratic-controlled state legislature while he was governor of Massachusetts, although he rarely mentions the hundreds of veto battles he had.
Obama's term has been littered with the legislative wreckage left behind by constant struggles with congressional Republicans. Yet his trip to New Jersey last Wednesday was a model of nonpartisanship as he accompanied Republican Gov. Chris Christie on a tour of destruction caused by Superstorm Sandy. The governor repeatedly praised Obama's response to the storm.