It's too early to call the race in Indiana, however, as expected, Obama has solidly won the North Carolina primary, thanks in part to his support among new voters and African Americans. Obama congratulated Clinton on her "apparent" win in Indiana, where her hold on white, blue-collar voters could help her squeak out a victory.
"This has been one of the longest, most closely fought contests in history," Obama said at a victory rally in Raleigh, N.C. Tuesday night. " And that's partly because we have such a formidable opponent in Senator Hillary Clinton."
In an apparent answer to Clinton's criticism that he is ill-prepared to withstand Republican attacks, Obama said: "The question, then, is not what kind of campaign they'll run, it's what kind of campaign we will run... I didn't get into race thinking that I could avoid this kind of politics, but I am running for President because this is the time to end it."
Black Voters Surge For Obama in N.C.
Support from 91 percent of African-Americans voters in N.C. -- who accounted for a third of voters in the state -- lifted Obama to easy victory, according to preliminary exit poll results.
The Illinois senator also benefited from a surge of new voters who favored Obama by a heavy margin.
The is slightly tighter in Indiana which was seen as Clinton's best chance for victory, with demographics similar to Ohio and Pennsylvania -- states she has won in the past.
The Obama campaign had hoped that a double victory for Obama would have swayed undecided superdelegates to his camp and increased pressure on Clinton to step out of the race. The former first lady trails Obama in the delegate count, the popular vote, and in the number of states won.
However a Clinton win in Indiana tonight will undoubtably fuel her argument that Obama's failure to reach white, blue-collar workers in states like Indiana could be a detriment in the general election fight against presumptive Republican nominee John McCain.
Primaries May Do Nothing to Change Status Quo
Battling to the end, the exhausted rivals urged North Carolina and Indiana voters to the polls Tuesday, each hoping to shake up a Democratic race that has gone on longer than anyone expected.
Obama dropped by a family restaurant in Greenwood, Ind., on Tuesday, eating an omelette and hash browns and chatting with diners. he later visited a polling station and played basketball with friends -- what has become a primary day ritual.
I think we've campaigned hard," Obama said Tuesday. "I think it's gonna be close. I don't think anybody really knows exactly what's gonna happen."
Highlighting her working-class message, Clinton visited the Indy 500 racetrack in Indianapolis with Sarah Fisher, a female race car driver who has endorsed her.
"We need to get on the track in America and get toward the finish line and change this country," Clinton said Tuesday.
Asked earlier today if she would drop out of the race if she lost tonight, Clinton refused to say.
"Politics is unpredictable. So I'm just going to wait and see what the voters have to say," she said.
Clinton Woos Blue-Collar Voters
After five months of bruising primary battles, Clinton has appeared to find a groove in recent weeks, defiantly refusing to withdraw from the race and pushing the party to seat delegates from Florida and Michigan.
She has continued to aggressively target blue collar and low-income voters, hammering her message that she will fight for them.
Indiana had many of the same demographics that have turned out for Clinton in recent primaries such as Ohio and Pennsylvania: white, rural, blue collar, low-education, women and older voters.
"You notice as she campaigns that she drops the ending of words, and becomes 'we're working people,'" said Peri Arnold, a professor of political science at the University of Notre Dame in South Bend, Ind. "She becomes sort of Rosie-on-the-night-shift and stylistically she becomes very attractive to these voters."
Obama has typically fared better among younger voters, people with higher-education, self-described liberals, and African Americans. Democratic strategists argue the candidates now need to show they can eat into each other's demographic base in order to pull away from the two-person race and claim victory.
"We're in demographic gridlock and we can't seem to get out of it," said Bill Carrick, a Democratic strategist unaffiliated with either candidate.
Obama, who went from living on food stamps as a child to becoming the first black president of the Harvard Law Review, has at times appeared uncomfortable in recent weeks trying to appeal to white, rural, working class voters by drinking beer and campaigning at construction sites and on factory floors.
"I think a lot of voters don't know what box to put this guy in," said Arnold, who focuses on presidential politics, arguing Obama's "cosmopolitanism" has confused voters.
"There are questions about Obama in many voters' minds about who he really is in terms of his style and his values and that's problematic because, after all, presidential politics is about connecting with the voters and giving voters a sense that they're like them in some way," he said.
Clinton, herself an Ivy League-educated millionaire and longtime Washington insider, has continued to paint Obama as an out-of-touch elitist and a flawed general election candidate. She has repeatedly argued that only she can withstand Republican attacks in the fall and right the wrongs of seven years of the Bush administration.
Despite her criticisms, a New York Times/CBS poll released Monday found Obama leads Clinton in support nationally, with 50 percent support for Obama to her 38 percent.
Bill Clinton Barnstorms Backwater Counties
Despite the negative tone of the campaign, the ongoing Democratic battle continues to energize voters and bring substantial turnout at the polls.
Obama's win in North Carolina comes despite the efforts of former President Bill Clinton, who campaigned persistently in the state over the last three weeks.
"Bill Clinton has been campaigning here pretty persistently for the last three weeks," said Steve Ford, editorial page editor of the Raleigh News & Observer.
"The Clintons have managed to target a constituency, generally smaller-town folks, and folks who may be more sensitive to economic problems than others and they have just very aggressively gone after them."
Candidates Sparred Over Gas Tax
In the two weeks since the Pennsylvania primary, Obama and Clinton have sparred over her proposed suspension of the 18-cents-a-gallon federal tax on gasoline for the summer travel season, with the estimated $8 million in lost revenue to be made up through a new tax on oil companies.
Several economists have derided her plan, and Obama called the proposal a gimmick designed to pander to low-income voters.
Meanwhile, last week Obama disavowed his pastor of 20 years, Rev. Jeremiah Wright, who in a series of public appearances reiterated some of his most controversial statements, including that the United States had created the virus that caused AIDS, that American foreign policies invited the 9/11 attacks, and other incendiary comments.
Preliminary exit poll results indicate that just under half of Democratic primary voters in Indiana and North Carolina alike call the controversy surrounding the Rev. Jeremiah Wright an important factor in their vote.
In both states around three-quarters of voters or more say they made up their minds before last week, according to preliminary exit polls, when the controversy over Wright's comments reignited.
In recent days Clinton has tried to re-set the bar for winning the Democratic nomination. Asked what she sees the finish line of the race as, she said for the first time: "I think it's 2209."
That figure 2209 delegates assumes that Florida and Michigan's delegates are included in the overall count. However, Democratic Party officials have long said the magic number for winning the nomination was 2025, a number that does not include Florida and Michigan, states that did not hold candidate-supported primaries after a bitter dispute with the national party over the primary calendar.
By re-setting the finish line, the Clinton campaign may be able to argue that Obama has not sufficiently won the race if he reaches or gets close to 2025.
"There are going to be the rest of these contests which are very significant and then in June if we haven't done it already were going to have to resolve Florida and Michigan. And they were legitimate elections," Clinton said Tuesday.
'Go to the Bitter End'
While voters continue to appear energized, many in the Democratic party worry the ongoing nomination battle will hurt the party going into the general election.
"We're beyond the point of this being good for the party," Carrick said. "We're getting to the point where it's just snarky, back-and-forth, gotcha stuff that's doing damage to the party."
Preliminary exit poll results indicate a continued criticism of Clinton for the tone of the campaign. In North Carolina two-thirds of voters said she attacked her opponent unfairly, as did about six in 10 in Indiana, reports ABC News' Gary Langer. Fewer in both states ? closer to four in 10 ? say Obama attacked unfairly.
Both candidates have suggested they expect to fight until the last primaries in Montana and South Dakota on June 3, and maybe even until the party convention in Denver this August, where superdelegates may ultimately decide the Democratic nominee.
"These two candidates are prepared to go to the bitter end," predicted Donna Brazile, who ran Al Gore's 2000 presidential campaign and is an ABC News contributor.
"They're committed. They have staff, they have offices, they have telephones, they have volunteers signed up," she said. "Some of them have already visited Oregon and Montana, so let's assume it's going until the bitter end."