NEW ADMINISTRATION:BARACK Obama will take office as the first black president of the United States with a decisive mandate and an expanded Democratic majority in both houses of Congress.
The Democrat captured a slew of battleground states that backed President George Bush in 2004, including Ohio, Florida, Colorado, Nevada, Indiana, New Mexico, Iowa and Virginia.
He fended off Republican John McCain's effort to prise Pennsylvania and New Hampshire from the Democratic column, so that with three states still to declare final results, Mr Obama held 349 electoral college votes to Mr McCain's 162.
The Democrats picked up at least five Senate seats and at least 19 in the House of Representatives, giving the party comfortable margins in both houses, although they were likely to fall short of the 60 Senate seats needed to block a filibuster.
In a sign that Democrats want to avoid mistakes made during past periods of dominance, the speaker of the house, Nancy Pelosi said she hoped the new president would "bring people together", before adding: "A new president must govern from the middle."
Faced with defeats on nearly all fronts, the Republicans must now regroup, decide on new leadership and seek to redefine their place in the American political landscape, though recriminations about the presidential campaign are likely to come first.
Mr Obama has indicated his willingness to reach across the aisle in making senior appointments but Republican senator Dick Luger, who was tipped by some as the president-elect's choice for the next secretary of state, has already made it clear that he would not accept an appointment.
Former secretary of state Colin Powell has also said he does not want a post.
Powell, who said that he cried watching television as the election was declared for Mr Obama, said yesterday: "I have to share in the pride that Americans have now for the fact America did this."
Former Democratic presidential candidate John Kerry is among those believed to be under consideration as secretary of state.
Names being floated for the key position of treasury secretary include Larry Summers, who held the post under president Bill Clinton, former Federal Reserve chairman Paul Volcker and New York Federal Reserve chief Jim Geithner.
Two members of the Kennedy political dynasty are being considered for posts: Robert F Kennedy jnr could take up a cabinet post as head of the Environmental Protection Agency, while his cousin, Caroline, may be offered the UN ambassadorship.
The man who will be the United States' 44th president is indebted to Senator Ted Kennedy and other members of the Kennedy family for endorsements during a key moment in his battle for the nomination.
Among the first to congratulate Mr Obama on his victory was his former rival for the Democratic nomination, New York senator Hillary Clinton.
"This was a long and hard- fought campaign but the result was well worth the wait. Together, under the leadership of President Barack Obama, vice-president Joe Biden, and a Democratic Congress, we will chart a better course to build a new economy and rebuild our leadership in the world.
"And I look forward to doing all that I can to support President Obama and vice-president Biden in the difficult work that lies ahead," she said.
"For too long, middle class families in this country have felt invisible, struggling alone as wages stagnate, jobs disappear, and the costs of daily life climb upward. In quiet, solitary acts of citizenship, American voters gave voice to their hopes and their values, voted for change, and refused to be invisible any longer."
Many Democrats were celebrating the defeat of two high-profile Republican senators, North Carolina's Elizabeth Dole, New Hampshire's John Sununu, and the Republicans' loss of its last remaining congressman in New England.
In his victory speech in Chicago, however, Mr Obama paid tribute to the Republican tradition, noting that the party had been founded by Abraham Lincoln on the values of self-reliance, individual liberty, and national unity.
"Those are values we all share, and while the Democratic Party has won a great victory tonight, we do so with a measure of humility and determination to heal the divides that have held back our progress," he said.
"As Lincoln said to a nation far more divided than ours: "We are not enemies, but friends . . . though passion may have strained it must not break our bonds of affection."
"And to those Americans whose support I have yet to earn - I may not have won your vote, but I hear your voices, I need your help, and I will be your president too."