INDIANAPOLIS - Democratic front-runner Barack Obama swept to victory in the North Carolina primary last night and lengthened his lead in the delegate race. Hillary Rodham Clinton led in Indiana as she struggled to stop her rival's march toward the party's presidential nomination.

"Tonight we stand less than 200 delegates away from winning the Democratic nomination for president of the United States," Obama told a raucous rally in Raleigh, N.C. - and left no doubt he intended to claim the prize.

He said it appeared Clinton had won Indiana's primary, although thousands of votes had yet to be counted in key counties.

Returns from 47 percent of North Carolina precincts showed Obama was winning 59 percent of the vote to 41 percent for Clinton, a triumph that mirrored his earlier wins in Southern states with large black populations.

Obama won at least 40 delegates and Clinton at least 31 in North Carolina, with 116 still to be awarded in the two states.

That made Indiana a virtual must-win Midwestern state for the former first lady, who was hoping to counter Obama's persistent delegate advantage with a strong run through the late primaries.

Returns from 40 percent of Indiana precincts showed Clinton with 56 percent of the vote to 44 percent for Obama.

The economy was the top issue by far in both states, according to interviews with voters as they left their polling places.

Indiana exit polls charted a racial divide that has become familiar in a long, historic campaign pitting a black man against a white woman.

Obama was gaining more than 90 percent of the black vote in Indiana, while Clinton was winning an estimated 61 percent of the white vote there, running ahead of her rival among white men as well as women.

She also had 51 percent of independents' votes, to 49 for her rival, a statistical tie, and was winning among Democrats, 53-47.

In North Carolina, Clinton won 60 percent of the white vote, but Obama claimed support from roughly 90 percent of black voters.

The impact of a long-running controversy over Obama's former pastor, the Rev. Jeremiah Wright, was difficult to measure.

In North Carolina, six in 10 voters who said Wright's incendiary comments affected their votes sided with Clinton. A somewhat larger percentage of voters who said the pastor's remarks did not matter supported Obama.

The effect of Clinton's call for a summertime suspension of the federal gasoline tax - which dominated the final days of the two primaries - was impossible to judge.

The questionnaire used to learn about voter motivation did not include any questions about the gasoline tax.

In Indiana, about one in five voters said they were independents, an additional one in 10 said Republican.

Only Democrats and unaffiliated voters were permitted to vote in North Carolina.

Obama began the day with 1,745.5 delegates, to 1,608 for Clinton, out of 2,025 needed for the nomination.

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.

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 269.5 to 255.

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." *