WASHINGTON — Barack Obama was elected the nation's first black president Tuesday night in a historic triumph that overcame racial barriers as old as America itself.

The son of a black father from Kenya and a white mother from Kansas, the Democratic senator from Illinois sealed his victory by defeating Republican Sen. John McCain in a string of wins in hard-fought battleground states – Ohio, Florida, Virginia and Iowa.

North Carolina remained up in the air as midnight approached. With 95 percent of the votes counted, Obama had a slight edge – fewer than 25,000 votes – over McCain.

A huge crowd in Grant Park in Chicago erupted in jubilation at the news of Obama's victory. Some wept.

McCain called his former rival to concede defeat – and the end of his own 10-year quest for the White House. "The American people have spoken, and spoken clearly," McCain told disappointed supporters in Arizona.

Obama and his running mate, Sen. Joseph Biden of Delaware, will take their oaths of office as president and vice president on Jan. 20, 2009.

As the 44th president, Obama will move into the Oval Office as leader of a country that is almost certainly in recession, and fighting two long wars, one in Iraq, the other in Afghanistan.

The popular vote was close, but not the count in the Electoral College, where it mattered most.

There, Obama's audacious decision to contest McCain in states that hadn't gone Democratic in years paid rich dividends.

Obama has said his first order of presidential business will be to tackle the economy. He has also pledged to withdraw most U.S. combat troops from Iraq within 16 months.

The 47-year-old Illinois senator was little known just four years ago. A widely praised speech at the Democratic National Convention, delivered when he was merely a candidate for the Senate, changed that.

Overnight he became a sought-after surrogate campaigner, and he had scarcely settled into his Senate seat when he began preparing for his run for the White House.

A survey of voters leaving polling places on Tuesday showed the economy was by far the top Election Day issue. Six in 10 voters said so, and none of the other top issues – energy, Iraq, terrorism and health care – was picked by more than one in 10.

Shortly after 11 p.m. in the East, The Associated Press count showed Obama with 338 electoral vote, well over the 270 needed for victory. McCain had 127 after winning states that comprised the normal Republican base.

The nationwide popular vote was remarkably close. Totals from 58 percent of the nation's precincts showed Obama with 51 percent and McCain with 47.9.