By Tom Cohen, CNN
WASHINGTON (CNN) -- President Barack Obama rode a wave of broad support from moderates, women and minorities to win re-election Tuesday by defeating Republican challenger Mitt Romney in Democratic strongholds and key battleground states.
According to CNN projections, Obama surpassed the decisive 270-vote threshold in the Electoral College with victory in Ohio. That and a later projected victory in another swing state -- Virginia -- gave him 303 electoral votes to 206 for Romney, according to the CNN call based on unofficial returns.
Joyful supporters danced and cheered at Obama's victory party in Chicago, and the president thanked them for ensuring the nation will continue to move forward while warning the battle for change they seek will continue to be difficult.
"Tonight, in this election, you, the American people, reminded us that while our road has been hard, while our journey has been long, we have picked ourselves up, we have fought our way back, and we know in our hearts that for the United States of America, the best is yet to come," Obama said to prolonged cheers.
He emphasized his main campaign theme of fighting for equal opportunity for all, saying the political arguments that come with democracy in America were a necessary part of the process.
"We will disagree, sometimes fiercely," Obama said, noting that "progress will come in fits and starts" and the victory Tuesday night "won't end all the gridlock."
Foreshadowing hard decisions ahead, the president said blind optimism and wishful idealism "can't substitute for the need to make difficult compromises to move forward."
When he finished, the first family, and Vice President Joe Biden and his family joined him onstage in a celebration of waves, hugs amid a blizzard of confetti.
In Boston, Romney supporters hugged and wept in a somber vigil while waiting for their candidate to concede.
In a brief speech delivered alone, Romney congratulated Obama and said his prayers would be with the president at such a challenging time for the country.
"At a time like this we can't risk partisan bickering and political posturing," Romney said, later adding that he wished he had "fulfilled your wishes to lead this great country in a different direction."
Romney's wife, Ann, and most of his family, as well as running mate Rep. Paul Ryan and his family, then came on the stage for a few minutes in what was a subdued farewell.
Obama withstood a late push by Romney in Pennsylvania and won battleground states of Ohio, Wisconsin and Iowa, according to CNN projections.
He also easily won traditional Democratic strongholds of California, New York and other populous states such as Michigan and Pennsylvania, where Romney mounted a late but unsuccessful push.
Obama received strong support, as expected, from women voters as well as overwhelming support from African-Americans. He also got strong backing from Hispanic voters, similar to the coalition that carried him to victory four years earlier to make him the nation's first African-American president.
Meanwhile, CNN projected that Democrats will retain their majority in the Senate, ensuring another divided Congress after Republicans earlier were projected to hold their majority in the U.S. House.
Obama and Romney ran dead even in final polls that hinted at a result rivaling some of the closest presidential elections in history, reflecting the deep political chasm in the country.
A heavy turnout was reported in much of the nation, and both campaigns expressed confidence that they would prevail.
As predicted, the election was decided in the battleground states, and as the returns emerged, it became clear that Romney was trailing.
Obama won his home state of Illinois as well as Romney' s home state of Massachusetts -- where the Republican previously served as governor. He also won Romney's birth state of Michigan, along with California, Ohio, Wisconsin, Iowa, Oregon, New Mexico, New Hampshire, Pennsylvania, Minnesota, New Jersey, New York, Vermont, Connecticut, Delaware, Maryland, Maine, Rhode Island and the District of Columbia, according to the CNN projections.
Romney won North Carolina, Idaho, Montana, Arizona, Kansas, Louisiana, Nebraska, North Dakota, South Dakota, Texas, Wyoming, Mississippi, Alabama, Tennessee, Arkansas, Kentucky, Indiana, West Virginia, South Carolina, Oklahoma, Utah, Missouri and Georgia, CNN projected.
With the victory, Obama faces a country with chronic federal deficits and debt as well as sluggish economic growth in the wake of a devastating recession and financial industry collapse that confronted him when he took office in January 2009.
Around the country, voters formed long lines at polling places after record numbers participated in early balloting, indicating a strong turnout.
Sporadic reports of irregularities included malfunctioning voting machines and other problems, including electoral hardships for some struggling to recover from the devastation of Superstorm Sandy in states in the northeast.
A judge in Philadelphia, a heavily Democratic city, ordered election officials to cover a mural of Obama at one school used as a polling location after Republicans complained the painting violated election laws.
Elsewhere in the city, GOP poll monitors were being escorted into precincts by sheriff's deputies after some observers had been denied access earlier in the day, said Tasha Jamerson, a spokeswoman for the district attorney's office.
In New Jersey, which permitted electronic balloting in the aftermath of last week's storm, the state chapter of the American Civil Liberties Union headed to court on Tuesday on behalf of voters who said their requests for an electronic ballot weren't being acknowledged.
Candidates usually take Election Day off, but both sides made public appearances even as voting was under way.
Obama visited a local Democratic election center in the Chicago area, while Vice President Joe Biden made "an unannounced but long-scheduled" stop in the key battleground state of Ohio.
Romney and his running mate, Rep. Paul Ryan, also arrived separately in Ohio, with Romney's campaign plane and Air Force Two, which carries the vice president, crossing paths at Cleveland's airport.
Only a handful of states were considered up for grabs and both candidates and their campaigns concluded an exhausting final sprint through them over the weekend and on Monday.
The barnstorming amounted to a montage of Americana electioneering, with Obama and Romney shouting themselves hoarse before boisterous crowds, joined by top surrogates and star power such as Bruce Springsteen singing for Obama and Kid Rock for Romney.
Emotion overtook the president at the end of the day.
His eyes welled with tears as he thanked the people "who've given so much to this campaign over the years," during a stop in Des Moines, Iowa -- a place where his first campaign gained an early foothold in his first run for the White House.
"You took this campaign and made it of your own and you organized yourselves block by block, neighborhood by neighborhood, county by county, starting a movement that spread across the country," Obama said wiping away tears as he talked.
For his part, Romney called Obama's record one of underachievement and failure, telling a cheering Virginia crowd at his second stop of the day that "almost every measure he took hurt the economy, hurt fellow Americans."
For Romney, a multimillionaire businessman seeking to become the nation's first Mormon president, the election concluded a six-year quest for the presidency.
Romney also failed in his first bid for the Republican nomination in 2008, then spent the next two years preparing for a second run that began in 2011 with a grueling primary campaign featuring a record 20 debates.
Romney, 65, shifted to the right for the primary race to overcome a broad field that included former House Speaker Newt Gingrich, former Pennsylvania Sen. Rick Santorum, Rep. Michele Bachmann of Minnesota, Texas Gov. Rick Perry, former U.S. Ambassador to China Jon Huntsman and businessman Herman Cain.
Romney declared himself "severely" conservative and adopted stances against abortion, gay marriage and a path to legal residency for undocumented immigrants while also opposing higher tax rates as part of a deficit reduction plan. His support remained steady -- though well below a majority -- throughout the primary campaign while opponents dropped out one by one until Romney emerged as the winner and claimed the nomination at the GOP convention in late August.
However, his campaign endured a tough September, due in part to some unforced errors. A secretly recorded video from a May fundraiser became public, showing Romney referring to 47% of the country as dependent on government handouts and therefore unreachable to him as a candidate.
When U.S. diplomatic compounds came under attack on September 11, including an assault that killed the U.S. ambassador and three other Americans in Benghazi, Libya, Romney quickly issued a statement that was criticized for mistaken information and seeking to politicize a sensitive national security issue.
In the first presidential debate on October 3, Romney began an energetic shift back to the political center and scored a clear victory over Obama by presenting himself as more moderate than the right-wing zealot portrayed by the president.
Obama's lackluster showing in the first debate contributed to an overwhelming consensus among analysts and poll results that Romney carried the night. He began rising in the polls to erase what had been a consistent Obama lead since the conventions a month earlier.
Stronger performances by Obama in the second and third debates slowed Romney's momentum.