Washington: US President Barack Obama and Republican Mitt Romney capped an aggressive, deeply negative and vastly expensive campaign and were awaiting the decision of voters Tuesday in an election that left Americans the choice of starkly different visions for the country's future.
At stake at the end of Election Day were overwhelmingly different approaches for healing the ailing US economy, polar opposite views on social issues from abortion rights for women to how to deal with immigration and the conduct of American foreign and military policy across the globe.
While nationwide polls going in to Election Day showed Obama and Romney virtually tied, the president was seen as holding slim leads in many of the nine swing states - Ohio chief among them -that were likely to determine the winner.
Exit polls found most voters saying the economy is the top issue facing the nation with three-fourths calling it poor or not so good.
The swing states were pulling outsized attention Tuesday night because the president is chosen in state-by-state contests, not according to the nationwide popular vote. The candidate who wins a state - with Maine and Nebraska the exceptions - is awarded all of that state's electoral votes, which are apportioned based on representation in Congress. Going into voting Tuesday, an Associated Press analysis of the states showed Obama with 243 electors in his column, 206 for Romney.
But with so many swing-state electors still up for grabs, there was a possibility of a repeat of the 2000 election, when the winner, George W. Bush, was not known for weeks after a protracted recount in Florida and a Supreme Court decision. A narrow victory for either candidate this time is sure to deepen polarization and leave the winner without a strong mandate to face mounting problems - notably, the "fiscal cliff" of higher taxes and deep automatic cuts in spending that loom in January if Republicans and Democrats in Congress cannot reach an accord on US finances.
Polls were closing first in Ohio and four other swing states in the eastern section of the United States - Florida, North Carolina, Virginia, and New Hampshire.
Moving west, the polls will then close next in the swing states of Wisconsin and Iowa in the Central time zone, then in Colorado and Nevada. The race was seen as so close that the outcome might not be known until the early hours of Wednesday or later.
Obama played basketball in a gymnasium near his home on Chicago's south side Tuesday afternoon as millions of Americans waited in long lines to cast their ballots. Earlier he was met with applause and tears from volunteers as he entered a campaign office before picking up a phone to call voters. He congratulated Romney on a "spirited campaign" and told reporters he's "confident we've got the votes to win, but it's going to depend ultimately on whether those votes turn out."
Romney and family were at his home near Boston to wait for the results after making two last campaign stops Tuesday with running mate Paul Ryan in Ohio and Pittsburgh, Pennsylvania. That state was thought to have been solidly in the Obama column but one where the Republican challenger had opened a last minute drive, a move seen as a bid to overcome a potential loss in Ohio. No Republican has ever captured the White House without carrying Ohio.
It wasn't just the presidency at stake Tuesday: All 435 seats in the House of Representatives, a third of the 100 Senate seats and 11 governorships were on the line, along with ballot proposals in some states on topics ranging from gay marriage to legalizing marijuana. Democrats were expected to maintain their majority in the Senate, with Republicans doing likewise in the House, raising the prospect of continued partisan wrangling no matter who might be president.
Obama and Romney have spent months highlighting their sharp divisions over the role of government in Americans' lives, especially in bringing down the stubbornly high unemployment rate, reducing the $1 trillion-plus federal budget deficit and reducing a national debt that has crept above $16 trillion.
Obama insists there is no way reduce the staggering debt and safeguard crucial social programs without asking the wealthy to pay their "fair share" in taxes. Romney, who claims his successful business background gives him the expertise to manage the economy, favors lowering taxes and easing regulations on businesses, saying it would spur job growth.
The economy has proven a huge drag on Obama's candidacy as he fought to turn it around after the deepest recession since the Great Depression of the 1930s, a downturn that was well under way when he replaced Bush in the White House on January 20, 2009.
No U.S. president since Franklin D Roosevelt in the 1930s has run for re-election with a national jobless rate as high as it is now - 7.9 per cent in October.
He ended the war in Iraq and the US intelligence and military tracked down and killed Osama bin Laden, but a new host of Middle East crises - especially the war in Syria and the deadly attack on the US Consulate in Libya - shadowed the last months of the campaign.
Obama, making his last run for office at age 51, credits his auto-industry bailout, stimulus plan and other policies for ending the recession and bring a slow but steady drop in the unemployment rate. Romney, 65, says Obama's policies have kept the economy at a standstill.
If elected, Romney would be the first Mormon US President. At times, the former Massachusetts governor has struggled to connect with the protestant evangelicals who are a core constituency of the Republican Party, especially because of his shifting positions on some social issues such as abortion.
Romney has worked doggedly to keep the race focused on the economy, and polls suggest that he succeeded in persuading many Americans he has the right credentials to steer America to better times. His selection of Ryan, a young and fiercely conservative Wisconsin congressman, as his running mate put Romney squarely on the side of the small-government Tea Party movement that has been a driving force of the Republican Party in recent years.