Clinton said it was "on to West Virginia, Kentucky, Oregon and the other states where people are eager to have their voices heard. She also insisted that the votes of Michigan and Florida be counted.
"But I can assure you," she also said, "no matter what happens, I will work for the nominee of the Democratic Party, because we must win in November."
Clinton faces a steeper challenge than perhaps at any time in the long campaign.
She had boasted last Friday that winning North Carolina would be "a game-changer," a claim that Obama highlighted in his victory speech. But in a sign that the most confrontational portion of the campaign is past, he also dropped a line from his prepared text that said Americans weren't looking for "more gimmicks," a dig at Clinton's gas-tax holiday proposal, which may well have worked against her and helped Obama, who strongly criticized it.
Clinton's double-digit loss in North Carolina likely dims, perhaps considerably, her chances of persuading Democratic superdelegates that Obama's candidacy had been irrevocably weakened by recent controversies over his comments about small-town residents and remarks by his former pastor, the Rev. Jeremiah A. Wright Jr.
The furor over Wright did not seem to be a decisive issue, exit polls showed, though white voters in North Carolina who called it important favored Clinton by better than a 5-1 margin.
Interviews with voters as they left their polling places showed that Obama had made modest gains in Indiana among white voters, including women and Catholics, groups he lost by 30 percentage points or more in neighboring Ohio in early March. In Indiana, Obama lost those groups by about 20 points, according to exit polling for the Associated Press and the TV networks.
Clinton did well enough among white voters, particularly those with less than a college education and with family incomes under $75,000, to make the Indiana contest close.
In North Carolina, demographics favored Obama. Black voters made up about one-third of the electorate and went for him by better than 10-1, repeating a pattern that was established in next-door South Carolina in January, when former President Bill Clinton made comments that angered black voters. Clinton won 60 percent of the white vote in North Carolina, not enough to overcome Obama's advantage among African Americans.
First-time primary voters cast about one-fifth of the ballots in each state and went for Obama by landslide margins, accounting for roughly half of his North Carolina victory margin.
