Democrat Barack Hussein Obama has been elected the first African-American president of the United States in a race that shattered racial barriers.
With polls now closed, the 47-year-old first-term senator from Illinois has captured the key states of Florida, Ohio, Pennsylvania, Colorado and California.
Those wins, combined with a slew of other states, have given him 338 electoral votes so far, more than enough to defeat Republican rival John McCain.
In a victory speech before a crowd of about 125,000 supporters in Chicago, Obama pledged to restore the country's standing in the world, tackle the financial crisis and reunite the population.
"We rise or fall as one nation, as one people," he said using words reminiscent of civil-rights leader Martin Luther King. "A new dawn of American leadership is at hand."
America's might, he said, does not come from the power of its military or the amount of its wealth but from the quality of its ideals – liberty, democracy and opportunity.
Admission of defeat
McCain, burdened with the baggage of a deeply unpopular president, could not overcome pollsters' predictions that the country had tipped decidedly toward his Democratic opponent.
As McCain lost New Hampshire, Virginia, Ohio and Pennsylvania – states where he had pinned his hopes for victory – an Obama victory seemed unavoidable.
"I pledge to him tonight to do all in my power to help him lead us through the many challenges we face," McCain conceded in his home state of Arizona.
"Today I was a candidate for the highest office in the country I love so much, and tonight, I remain her servant."
Bush also called Obama to congratulate him and invite him to the White House.
Throughout the country as precincts closed and a Democrat victory seemed at hand, Americans rolled into the streets waving flags and chanting "Yes, we can" a refrain from the Obama campaign that hinged on a message of hope and change.
The campaign, which lasted roughly two years, was one of the longest in the country's history. It was also the most expensive. Obama, who mobilised a massive fund-raising and voter registration network, raised $639 million (SFr747 million) compared to McCain's $335.3 million.
In 1996 entire spending between both parties amounted to $478 million.
Obama will officially take office on January 20, 2009.
In Switzerland, President Pascal Couchepin hailed Obama's election as "the choice of the future".
"America has shown it is capable of opening new frontiers," he said.
swissinfo with agencies
Stock markets react
The Swiss stock market index (SMI) of leading firms bucked a global trend by starting the day in negative territory following the conclusion of the US Presidential election.
Shares in the US and in Asia closed higher while European stock markets were bouyant on opening, before falling into the red by mid-morning.
The SMI, in contrast, immediately lost ground despite optimism in some quarters that the newly elected US President Barack Obama could stimulate the economy.
Markets appeared to react to further gloomy economic data from the US and a series of profit warnings from leading companies.