CBS News early exit poll results show that most voters in both states made up their minds a while ago. Only 17 percent in Indiana and 14 percent in North Carolina decided in the last three days. Twenty-four percent in Indiana and 18 percent in North Carolina decided in the last week.
Late deciders backed Clinton in Indiana by a margin of 62 percent to 38 percent for Obama. In North Carolina, Obama won late deciders by a much smaller margin of 49 percent to 48 percent.
As it has been throughout the Democratic primaries, the economy was the most important issue in both states with 65 percent of voters in Indiana describing it as such and 60 percent in North Carolina. In Indiana, 50 percent of voters said Clinton would be more likely to improve the economy and 46 percent said that Obama would. In North Carolina, 52 percent said that Obama would be more likely to improve the economy and 42 percent said that Clinton would.
Nearly half of voters in both states said the situation with Obama's former pastor Reverend Wright was important in their vote, while half said that it was not. In Indiana, 48 percent said that it was important and 49 percent said that it was not, while in North Carolina, 48 percent said the Wright situation was important in their vote and 50 percent said that it was not.
In both states, more voters thought that Clinton attacked Obama unfairly than vice-versa. Sixty-three percent of Indiana voters and 67 percent of North Carolina voters thought Clinton attacked her opponent unfairly, while only 43 percent in Indiana and 40 percent in North Carolina thought that Obama unfairly attacked Clinton.
Looking ahead to the general election, CBS News early exit polls showed that the majority of voters said that they would not be satisfied if the Democratic candidate they did not support were to become the nominee. Only 36 percent of Clinton voters in Indiana and 34 percent in North Carolina said they would be satisfied with Obama. Forty-one percent of Obama voters in Indiana and 44 percent in North Carolina would be satisfied if Clinton becomes the Democratic nominee.
Forty-eight percent of voters in Indiana thought that Clinton could beat presumptive Republican nominee John McCain in the general election, and the same percentage thought that Obama could win in November. In North Carolina, 40 percent thought that Clinton could beat McCain and 54 percent thought that Obama could beat the Arizona senator.
Obama began the day with 1,745 delegates to 1,603 for Clinton in the latest CBS News delegate count. 2,025 are needed for the nomination.
The Clinton camp expected to win in Indiana and lose in North Carolina, reports CBS News chief White House correspondent Jim Axelrod. If that's what happens, the race goes on.
Both races were dominated in the final days by Clinton's call for a summertime suspension of the federal gasoline tax, an issue that she created after scoring a victory in the Pennsylvania primary two weeks ago.
Obama ridiculed the proposal as a stunt that would cost jobs, not the break for consumers she claimed. The two rivals dug in, devoting personal campaign time and television commercials to the issue.
Indiana had 72 delegates at stake, and Clinton projected confidence about the results by arranging a primary-night appearance in Indianapolis.
North Carolina had 115 delegates at stake, and Obama countered with a rally in Raleigh.
"Barring a sweep from either candidate, this race is likely to go through the end of the contests on June 3rd," said CBSNews.com senior political editor Vaughn Ververs. "This is the last big primary day with a significant chunk of delegates available, but it's unlikely to be decisive. If not, it may well be the superdelegates who will determine the party's nominee for the fall."
The rivals made their final appeals in Indiana as the polls opened, the former first lady at the famed Indianapolis Motor Speedway, and Obama greeting early morning diners at a restaurant.
Clinton declined to offer a prediction about the outcome. Obama wouldn't either, except to say, "I think it's going to be close."
Obama leads Clinton in delegates won in primaries and caucuses. Despite his defeat two weeks ago, he has steadily whittled away at her advantage in superdelegates in the past two weeks and trails 257 to 271.
Clinton saved her candidacy with her win in Pennsylvania, and she campaigned aggressively in Indiana in hopes of denying Obama a victory next door to his home state of Illinois. Indiana is home to large numbers of blue-collar workers who have been attracted to the former first lady, and she sought to use her call for a federal gas tax holiday to draw them and other economically pinched voters closer.
Inevitably, the issue quickly took on larger dimensions.
Obama said it symbolized a candidacy consisting of "phony ideas, calculated to win elections instead of actually solving problems."
Clinton retorted, "Instead of attacking the problem, he's attacking my solutions," and ran an ad in the campaign's final hours that said she "gets it."
To a large extent, the gasoline tax eclipsed the controversy surrounding Obama's former pastor. After saying several weeks earlier he could not disown the Rev. Jeremiah Wright for his fiery sermons, Obama did precisely that when the minister embarked on a media tour.
At a news conference in North Carolina last week, Obama equated Wright's comments with "giving comfort to those who prey on hate."
The balance of the primary schedule includes West Virginia, with 28 delegates on May 13; Oregon with 52 and Kentucky with 51 a week later; Puerto Rico with 55 delegates on June 1, and Montana with 16 and South Dakota with 15 on June 3.
Sen. John McCain of Arizona, the Republican nomination already in hand, campaigned in North Carolina and assailed Obama for his vote against confirmation of Chief Justice John Roberts.
"Senator Obama in particular likes to talk up his background as a lecturer on law, and also as someone who can work across the aisle to get things done," McCain said. "But ... he went right along with the partisan crowd, and was among the 22 senators to vote against this highly qualified nominee."
Clinton also voted against Roberts, but McCain, as if often the case, focused his remarks on Obama.
Obama's campaign responded that the Republican would pick judges who represent a threat to abortion rights and to McCain's own legislation to limit the role of money in political campaigns.
©MMVIII, CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.