2:24AM EST November 7. 2012 - President Obama won re-election to the White House Tuesday, defeating Republican challenger Mitt Romney in the nation's costliest, and perhaps most bitterly contested campaign - one that ultimately came down to winning a handful of key battleground states.
Obama and Romney were in a virtual tie in most polls in the closing days of the election, with several swing states up for grabs. But Obama won virtually every critical battleground state, including Ohio, which pushed him over a majority of electoral votes and prompting widespread celebration among supporters of the president.
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In Chicago, Obama greeted a throng of well-wishers at 1:35 ET with his wife, Michelle, and daughters Malia and Sasha at his side. "Tonight, more than 200 years after a former colony won the right to determine its own destiny, the task of protecting our Union moves forward. It moves forward because of you," Obama said. "Tonight, in this election, you, the American people reminded us that while our road has been hard ... we have picked ourselves up, and for the United States of America, the best is yet to come."
Acknowledging the deep divisiveness that has polarized much of the nation, Obama vowed to work with GOP leaders on major looming issues, including the deficit, tax code and reinvigorating the economy.
Obama won at least 25 states, capturing 303 electoral votes, but held just a slim lead in the popular vote. Romney, who won 24, said in his concession speech that it was time to end bipartisan bickering.
"This is a time of great challenge for America, and I pray the president will be successful in guiding our nation,'' Romney said.
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"The nation is at a critical point. At a time like this, we can't risk partisan bickering," said Romney, who urged Democrats and Republicans to work together on key issues, such as reviving the economy and growing jobs.
Democrats held their narrow majority in the Senate on Tuesday, grabbing Republican seats in Massachusetts and Indiana and turning aside GOP challenges in Missouri, Virginia, Pennsylvania and Ohio.
Republicans were well on the way to retaining control of the House of Representatives, ensuring that Congress will be divided at the start of Obama's second term.
One of the smallest of the battleground states, New Hampshire, went for Obama. So did Nevada, a state that went for Obama in 2008. Obama made 10 trips to the state, beset with the nation's highest unemployment rate and one of the nation's highest home foreclosure rates. Another toss-up state, Colorado, also went for Obama. The president won Pennsylvania, a state Romney looked to late in the campaign for a potential upset.
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Exit polls of voters leaving their voting places suggested a razor-close outcome in a deeply divided nation, with the incumbent holding a small advantage, 51%-47%. That finding was from a survey of more than 25,565 voters nationally.
All told, Obama won at least 25 states, while Romney won at least 22 states, including much of the South, Plains and Mountain West. On the West Coast, Obama won California and Washington.
Obama won two of Romney's home states - Massachusetts, where the Republican won one election as governor, and Michigan, where Romney was born. Romney also has a home in New Hampshire, where he lost.
Obama's strength was in the Northeast and parts of the Mid-Atlantic region, including New York. He won his home state of Illinois as well as Vice President Biden's Delaware.
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Exit polls of voters in key states showed the economy was the top issue on voters' minds, and on that and other key issues the nation remains sharply divided. It was clear that Obama would not do as well as he did in 2008, when he won with a 7.3% margin of the popular vote.
The exit polls suggested Romney won among men by double digits. Obama won among women, who were a focus of much of the campaign, but by a smaller margin than four years ago.
The polling also suggested Romney had a narrow advantage among suburban voters, who were critical for Obama's 2008 election. The president retained a strong lead in cities.
The president appeared to have gained an edge among late-deciding voters, exit polls suggested. Among those who decided who to vote for in the last few days, 49% voted for Obama, 46% for Romney. Among those who said Obama's response to Hurricane Sandy was important to their vote, Obama was favored by almost 2-1.
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Romney made final Election Day campaign dashes to Ohio and Pennsylvania. Biden matched the late GOP campaigning with his own Ohio appearance, while Obama made calls from a campaign office in Chicago and relaxed with a game of basketball.
Across battleground states where the outcome was in doubt, and where both candidates focused most of their energies and money, more than a million political commercials aired on TV during the long campaign. But after 17 months and more than $2 billion spent by each presidential candidate, it was up to the people who flooded churches, schools and auditoriums to cast ballots.
The struggling economy was on voters minds.
"Business is rough. Everybody wants someone to blame," said Frank Robles, 45, who employs 15 at his North Las Vegas shoe store. Yet Robles is supporting Obama, saying he's not responsible for the worst of the economic crisis: "People need to give him a chance."
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But A.J. Jotipra, 69, a retired IBM worker says Obama has had his chance. Jotipra lost his Henderson, Nev., house to foreclosure last year. "The last four years, Obama has done nothing," Jotipra says.
In Ohio, the atmosphere at some polling places was informal and happy, despite the barrage of negative TV ads.
Retired nurse Nancy Manion, 74, of Dublin, Ohio, was excited to vote for Romney "to put God back in schools." But she also was thankful that campaign ads would end.
"Too many ads, too much slander," Manion says.
In Northern Virginia, Robert Adams, who has doctorates in business and psychology, said he voted for Romney and had four words to describe the campaign: "Too long. Too noisy." He said that "after awhile I just had the mute button on the television all the time."
In Dixville Notch, N.H., one of two tiny New Hampshire villages that get to cast the first votes of the presidential election, Obama and Romney tied with five votes each - something that has never happened before.
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"I'm bewildered, that's the best way to describe my reaction," said voter Peter Johnson, adding he didn't think that Obama would get that many votes.
Besides long lines at polling places there are disputes over voter identification. Tuesday's vote is already being challenged in some locations.
New York and New Jersey were still scrambling to resolve voting problems created by Sandy. New Jersey said it would expand online voting for those whose polling places have been disrupted, a move New York election officials rejected. New York has also had to relocate polling places, which could create voting challenges.
Voters were taking special election shuttles from storm-hit areas and voting by affidavit from any polling place they could reach after officials put emergency measures in place.
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"It's important because it's our day," said Agim Coma, a 25-year-old construction worker who lost his apartment and car to the storm but was first in line to vote in one New Jersey town. "No matter what happens - hurricanes, tornadoes - it's our day to vote."
Ohio, Pennsylvania and Florida - all critical swing states for the presidential election - have faced pitched battles throughout the summer over voter-identification laws. As late as last week, Ohio election officials were issuing new rules for what ID is required and how the voter's identification should be certified.
In New London, Pa., a long line snaked out the door as hundreds came to vote.
Poll workers asked voters for identification but didn't require it. State legislators passed a voter-ID law earlier this year, but a state court blocked its implementation out of concerns it would disenfranchise legitimate voters who couldn't get identification.
If voters did not have identification, they were given a flier explaining the law "for coming elections."
In Jefferson, Wis., a steady stream of voters filed into City Hall. Mark McQuin, 39, a project manager, voted for Obama but said what many people were thinking: "I'm ready for it to be over."
Contributing: Carolyn Pesce in McLean, Va., Julie Schmit, Nevada; Judy Keen in Wisconsin; Chuck Raasch, Alexandria, Va.; Dennis Cauchon in Ohio; Yamiche Alcindor, Denver; Donna Leinwand Leger, Orlando; Gregory Korte, Washington, D.C.; Melanie Eversley, New York; Mike Chalmers in Pennsylvania; Gary Stoller, Connecticut; Florida Today; Louisville Courier Journal; Detroit Free Press; Greenville (S.C.) News; and The Associated Press.