Sen. Barack Obama scored a landslide victory in North Carolina's Democratic presidential primary yesterday, moving him ever closer to locking up an insurmountable lead among pledged delegates, while Sen. Hillary Rodham Clinton posted a razor-thin win in the hotly contested Indiana primary as she sought to keep her shaky candidacy for the nomination alive.

Clinton secured the Indiana result despite the late rush of votes for Obama from the city of Gary and surrounding Lake County that dramatically narrowed her margin in a bizarre end to a long night of counting. Inexplicably, Lake County did not report any votes until nearly 11:30 p.m. Eastern time, and was still reporting precinct results after 1 a.m. this morning.

The results of the two primaries solidified the status quo in the Democratic race, but one that now gives Obama the clear advantage in the battle for the nomination because of his solid lead in the tally of pledged delegates.

Despite her Indiana victory, Clinton emerged even more the underdog in the nomination battle.

The results meant the senator from Illinois adds both to his pledged-delegate margin and his lead in the popular vote, leaving Clinton with an even more daunting challenge in trying to deny Obama the nomination.

Although she managed to squeeze out a victory in Indiana, the night produced a far different outcome than the Clinton campaign had hoped for. In the closing hours of the campaigns in the two states, her advisers had expressed confidence that she was gaining ground on Obama in North Carolina rapidly enough to hold his anticipated victory margin to single digits. They also thought she was positioned for a solid victory in Indiana.

Instead, Obama won North Carolina by 56 percent to 42 percent, and his popular-vote margin there — about 230,000 votes — wiped out the gains Clinton had made with her decisive victory in Pennsylvania two weeks ago. In Indiana, Clinton won by 51 percent to 49 percent.

Obama, noting that he is now fewer than 200 delegates away from locking up the nomination, used his victory speech in Raleigh to try to help heal the divisions in the party that have resulted from the long and difficult campaign and to sound the themes of a general-election race against Sen. John McCain, the presumptive Republican nominee.

"This fall, we intend to march forward as one Democratic Party, united by a common vision for this country," he said. "Because we all agree that at this defining moment in history — a moment when we're facing two wars, an economy in turmoil, a planet in peril, a dream that feels like it's slipping away for too many Americans — we can't afford to give John McCain the chance to serve out George Bush's third term. We need change in America."

Clinton appeared more than a hour after Obama spoke, before any final call on Indiana had been made, to declare that she will continue fighting. "Tonight we've come from behind," she said. "We've broken the tie, and thanks to you it's full speed — on to the White House."

But there were other signals that she and her advisers recognize the long odds she faces. Her speech was tinged with a sense of urgency, as she pleaded with her supporters to go immediately to her Web site and make a contribution to allow her to continue to campaign against a rival who enjoys a sizable financial advantage.

And, like Obama, she pledged to help unify the party, regardless of the outcome. "No matter what happens, I will work for the Democratic nominee, because we must win in November," she said.

ROUGH WEEKS

Yesterday's voting came after the most difficult month of the campaign for Obama. Clinton had gained momentum by winning in Pennsylvania two weeks ago, and Obama's momentum slowed when his former pastor, the Rev. Jeremiah Wright Jr., went on a public relations tour making controversial statements. Obama finally made an emphatic break with Wright a week before the primaries in Indiana and North Carolina.

In North Carolina, Obama brushed aside a determined effort by Clinton, whose campaign believed her populist economic message and proposal for a summer suspension of the federal gasoline tax were helping her to gain ground there against her heavily favored rival. Overwhelming support from African-American voters, who made up a third of the electorate, helped seal the Obama victory.

In Indiana, Clinton built her initial lead with strong support among white voters, particularly working-class whites who had become the focus of both candidates. Obama enjoyed an advantage in northwestern Indiana because of its proximity to his home in Chicago, but Clinton had solid support in more culturally conservative southern Indiana.

TALLYING UP

At stake yesterday were 187 pledged delegates — 115 in North Carolina and 72 in Indiana. That made yesterday the third-biggest day of the long nomination battle in terms of delegates. But more important, it was the last big day on the calendar.

Obama won at least 94 delegates and Clinton at least 75 in the two states combined, with 18 still to be awarded.

An additional 217 pledged delegates remain to be chosen in the final six contests between now and June 3: 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.

Obama's delegate haul edged him closer to his prize — 1,840 to 1,684 for Clinton in the Associated Press count, out of 2,025 needed to win the nomination.

Included in that count are superdelegates — elected officials and party leaders who are automatically granted a vote at the Democratic National Convention in Denver. The AP tally showed Clinton with 270 superdelegates and Obama with 256.

The Washington Post and Associated Press contributed to this report.