Barack Obama has defeated the Republican candidate, Mitt Romney in an extraordinarily tight battle for the White House.

The Democrat was swept back to the White House, holding off the Republican challenger in the key states of Ohio and Iowa.

In a tweet even before the result was declared, President Obama said: “This happened because of you. Thank you.”

It had been predicted to be a close race but in the end Romney’s campaign failed to catch fire and Obama scored a comfortable win in the battleground states.

Romney was unable to penetrate the Democrat firewall put up around Wisconsin, Pennsylvania and Michigan despite spending millions of dollars on TV ads.

Florida and Virginia have yet to declare but the Ohio forecast secured Obama his second – and final – four-year term.

Voter turnout was reported to be high, with long queues at some polling stations following the most expensive presidential battle in US history at a cost of $2 billion.

The president had spent the day playing basketball in a gym near his home in Chicago and told reporters he was “confident we’ve got the votes to win”.

President Obama sent another tweet thanking his supporters: “We’re all in this together. That’s how we campaigned, and that’s who we are. Thank you.- BO”

The economy proved a huge drag 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 George W Bush in the White House on January 20, 2009.

No US president since Franklin D. Roosevelt in the 1930s had run for re-election with a national jobless rate as high as it is now – 7.9%.

In foreign policy, Obama ended the war in Iraq and the US intelligence and military tracked down and killed Osama bin Laden.

However, a new host of Middle East crises – especially the war in Syria and the deadly attack on the US Consulate in Libya – overshadowed the last months of the campaign.

Win not by accident

President Obama has told supporters his win “wasn’t fate and it wasn’t an accident”.

In an email sent to people signed up to his campaign, he said: “Friend, I’m about to go speak to the crowd here in Chicago, but I wanted to thank you first.

“I want you to know that this wasn’t fate, and it wasn’t an accident. You made this happen.

“You organised yourselves block by block. You took ownership of this campaign five and ten dollars at a time. And when it wasn’t easy, you pressed forward.

“I will spend the rest of my presidency honouring your support, and doing what I can to finish what we started.

“But I want you to take real pride, as I do, in how we got the chance in the first place.

“Today is the clearest proof yet that, against the odds, ordinary Americans can overcome powerful interests.

“There’s a lot more work to do.

“But for right now: Thank you.

Barack”

People before politics

Mr Romney in his brief concession speech advised all politicians both of the Democratic and Republican parties to put the American people before politics.

“I have just called President Obama to congratulate him,” he said.

He told Republican supporters in Boston: “I pray that the president will be successful in guiding our nation.”

Mr Romney said: “I want to thank Paul Ryan for all that he has done for our campaign.

“And for our country. Besides my wife, Ann, Paul is the best choice I’ve ever made.

“And I trust that his intellect and his hard work and his commitment to principle will continue to contribute to the good of our nation.

“I also want to thank Ann, the love of my life.

“She would have been a wonderful first lady. She’s been that and more to me and to our family and to the many people that she has touched with her compassion and her care.

“I thank my sons for their tireless work on behalf of the campaign, and thank their wives and children for taking up the slack as their husbands and dads have spent so many weeks away from home.

“I want to thank Matt Rhoades and the dedicated campaign team he led.

“They have made an extraordinary effort not just for me, but also for the country that we love.

“And to you here tonight, and to the team across the country – the volunteers, the fundraisers, the donors, the surrogates – I don’t believe that there’s ever been an effort in our party that can compare with what you have done over these past years. Thank you so very much.

“Thanks for all the hours of work, for the calls, for the speeches and appearances, for the resources and for the prayers. You gave deeply from yourselves and performed magnificently. And you inspired us and you humbled us. You’ve been the very best we could have imagined.

“The nation, as you know, is at a critical point. At a time like this, we can’t risk partisan bickering and political posturing. Our leaders have to reach across the aisle to do the people’s work.

“And we citizens also have to rise to the occasion. We look to our teachers and professors; we count on you not just to teach, but to inspire our children with a passion for learning and discovery.

“We look to our pastors and priests and rabbis and counselors of all kinds to testify of the enduring principles upon which our society is built: honesty, charity, integrity and family.

“We look to our parents, for in the final analysis everything depends on the success of our homes.

“We look to job creators of all kinds. We’re counting on you to invest, to hire, to step forward.

“And we look to Democrats and Republicans in government at all levels to put the people before the politics.

“I believe in America. I believe in the people of America.

“And I ran for office because I’m concerned about America. This election is over, but our principles endure. I believe that the principles upon which this nation was founded are the only sure guide to a resurgent economy and to renewed greatness.

“Like so many of you, Paul and I have left everything on the field. We have given our all to this campaign.

“I so wish – I so wish that I had been able to fulfill your hopes to lead the country in a different direction, but the nation chose another leader. And so Ann and I join with you to earnestly pray for him and for this great nation.

“Thank you, and God bless America. You guys are the best. Thank you so much. Thank you. Thanks, guys.”