Obama rolls to re-election over Mitt Romney

President Barack Obama rolled to re-election and a second term in the White House on Tuesday with a victory over Republican challenger Mitt Romney as the Democrat overcame deep doubts about his handling of the U.S. economy.

Romney, closeted with advisers in Boston, did not immediately concede defeat because of questions about whether Obama had really won the pivotal state of Ohio. But other projected Obama victories in Virginia, Nevada, Iowa and Colorado carried the president past the 270 electoral votes needed for victory.

Obama, America's first black president, won by convincing voters to stick with him as he tries to reignite strong economic growth and recover from the worst recession since the Great Depression of the 1930s. An uneven recovery has been showing some signs of strength but the country's 7.9 percent jobless rate remains stubbornly high.

Obama's victory in the hotly contested swing state of Ohio - as projected by TV networks - was a major step in the fight for the 270 electoral votes needed to clinch the White House and ended Romney's hopes of pulling off a string of swing-state upsets.

Obama scored narrow wins in Ohio, Wisconsin, Iowa, Pennsylvania and New Hampshire - all states that Romney had contested - while the only swing state captured by Romney was North Carolina, according to television network projections.

The nationwide popular vote remained extremely close. There was no immediate word from the Romney camp on the reported results, with some Republicans questioning whether Obama had in fact won Ohio despite the decisions by election experts at all the major TV networks to declare it for the president.

The later additional of Colorado and Virginia to Obama's tally - according to network projections - meant that even if the final result from Ohio is reversed, Romney still could not reach the needed number of electoral votes in America's state-by-state system of choosing a president.

While Obama supporters in Chicago were ecstatic, Romney's Boston event was grim as the news was announced on television screens there. A steady stream of people left the ballroom at the Boston convention center.