President Barack Obama won re-election to a second term in a close race against Republican challenger Mitt Romney. Growing optimism about the economy and a big voter turnout among Democrats appeared to make the difference.

Reaction to President Barack Obama's victory was swift and passionate. Across the country, Obama supporters cheered. Supporters of Mitt Romney were left wondering why the Republican's White House bid fell short.

In his victory speech, President Obama pledged to work with Congress to solve the nation's problems.

"And in the coming weeks and months I am looking forward to reaching out and working with leaders of both parties to meet the challenges we can only solve together," he said. "Reducing our deficit. Reforming our tax code. We have got more work do."

Romney said it's time to put partisan politics aside and work together for the good of the country.

"This is a time of great challenges for America, and I pray that the president will be successful in guiding our nation," said Romney.

The economy ranked as the top issue by nearly 60 percent of voters surveyed as they left polling places. Analysts say an improved economy made the difference in the key state of Ohio, where President Obama was credited with preventing the collapse of the US auto industry and saving jobs.

"It is not campaigns that decide elections, it is governing," said Allan Lichtman, a political science professor at American University in Washington. "And it's not just the economy, but it is a broad range of governing factors."

Another surprise of this election was the gender gap. Obama won women voters, while a majority of men voted for Romney. President Obama also did well with minorities, especially Hispanics, who gave Democrats their largest margin of support since 1996.

Lichtman says the Republican Party needs to broaden its support.

"The Republican Party will not survive unless it figures out a way, and that is going to be really hard to appeal to minorities and to appeal to women, given their stance on abortion, on immigration, on civil rights," he said. "That is a task for Republicans."

Obama will again face a divided Congress. Democrats retained control of the U.S. Senate while Republicans kept control of the House of Representatives.

Analysts say the president's supporters know their celebration could be short lived unless he and lawmakers find common ground to solve the nation's pressing problems.

President Barack Obama won re-election to a second term in a close race against Republican challenger Mitt Romney. Growing optimism about the economy and a big voter turnout among Democrats appeared to make the difference.

Reaction to President Barack Obama's victory was swift and passionate. Across the country, Obama supporters cheered. Supporters of Mitt Romney were left wondering why the Republican's White House bid fell short.

In his victory speech, President Obama pledged to work with Congress to solve the nation's problems.

"And in the coming weeks and months I am looking forward to reaching out and working with leaders of both parties to meet the challenges we can only solve together," he said. "Reducing our deficit. Reforming our tax code. We have got more work do."

Romney said it's time to put partisan politics aside and work together for the good of the country.

"This is a time of great challenges for America, and I pray that the president will be successful in guiding our nation," said Romney.

The economy ranked as the top issue by nearly 60 percent of voters surveyed as they left polling places. Analysts say an improved economy made the difference in the key state of Ohio, where President Obama was credited with preventing the collapse of the US auto industry and saving jobs.

"It is not campaigns that decide elections, it is governing," said Allan Lichtman, a political science professor at American University in Washington. "And it's not just the economy, but it is a broad range of governing factors."

Another surprise of this election was the gender gap. Obama won women voters, while a majority of men voted for Romney. President Obama also did well with minorities, especially Hispanics, who gave Democrats their largest margin of support since 1996.

Lichtman says the Republican Party needs to broaden its support.

"The Republican Party will not survive unless it figures out a way, and that is going to be really hard to appeal to minorities and to appeal to women, given their stance on abortion, on immigration, on civil rights," he said. "That is a task for Republicans."

Obama will again face a divided Congress. Democrats retained control of the U.S. Senate while Republicans kept control of the House of Representatives.

Analysts say the president's supporters know their celebration could be short lived unless he and lawmakers find common ground to solve the nation's pressing problems.