WASHINGTON Sen. Barack Obama won a blowout Tuesday in North Carolina, putting him closer than ever to claiming the nomination. But Sen. Hillary Rodham Clinton clung to a narrow lead in Indiana, allowing her to survive but weakening her case for help from Democratic superdelegates.</p><p>"Tonight we stand less than 200 delegates away from securing the Democratic nomination," Obama told a cheering crowd in Raleigh, N.C. "We can't afford to give John McCain the chance to serve out George Bush's third term . . . That's why we will be united in November."</p><p>By winning the night's bigger prize by a wide margin, Obama stretched his delegate and vote lead. That served up a resounding rebuttal to Clinton's claim of momentum since her big win in Pennsylvania two weeks ago.</p><p>But with only a half-dozen primaries left, he can't clinch without help from party elders.</p><p>There are now more undeclared superdelegates than delegates at stake in remaining states.</p><p>For Clinton, viability may now hinge on whether the party lifts sanctions against Florida and Michigan for holding early primaries. She has stepped up demands that those delegates be counted. Without them, the target is 2,025. With them, the magic number is 2,209.</p><p>"I don't think either one of them has any quit in them at this point," said Boyd Richie, chairman of the Texas Democratic Party, one of the dwindling number of uncommitted superdelegates. "It's obviously looking more and more and more at this point that it goes to the convention . . . Sure I'm worried about it. But that's the process."</p><p>Obama has just come through the roughest patch of his campaign, shaking off persistent questions about his former pastor's inflammatory views and his own gaffe about "bitter" small town residents. Tuesday showed he can shake off adversity, and he clearly framed his victory speech to signal that he views McCain as his main opponent now.</p><p>Clinton wasn't ready to back down, though.</p><p>She tweaked Obama for calling Indiana a "tie-breaker" state. "Tonight, we've come from behind. We've broken the tie and thanks to you it's full speed onto the White House," Clinton told supporters in Indianapolis, cheering as if there had been no setback.</p><p>The split decision left the race in flux, it did cement one thing: the image of a party divided along racial and class lines.</p><p>Exit polls showed Clinton with a firm grip on working class whites - a key swing bloc in states Democrats need in the fall - while black voters overwhelmingly support Obama, along with wealthier and better-educated voters of all ethnicities. And more partisans than ever on each side told pollsters they'd rather vote for McCain, or stay home, than vote for the other Democrat.</p><p>"I do think the end is in sight," said David Bositis, who studies the black electorate at the Joint Center for Political and Economic Studies, predicting that the eventual nominee will be able to restore the traditional voting coalition between blacks and working class whites. He also predicted that, once the final contests are held, superdelegates will fall in behind the candidate with more states, votes and delegates. "Obama will be recognized as the legitimate nominee."</p><p>Party leaders confess some anxiety. House Majority Leader Steny Hoyer, D-Md., said Tuesday he's toyed with calling in the 70 or so undeclared House members to force a discussion on what's best for the party and "try to bring some clarity to the race."</p><p>Tuesday's contests were by far the biggest left on the calendar: 115 delegates at stake in North Carolina, 72 in Indiana. Obama started the day ahead by 137 delegates, needing 280 more to clinch. Clinton needed 417.</p><p>West Virginia votes next Tuesday, Oregon and Kentucky a week later. The biggest prize left is Puerto Rico on June 1. Montana and South Dakota get the final word on June 3. Combined, that's 217 delegates - too few to shift the outcome.</p><p>"They're small states," said Larry Sabato, director of the University of Virginia Center for Politics, adding that superdelegates will have to move quickly.</p><p>"Just about everybody realizes that it's a disaster for the Democrats if they go into the convention without a clear nominee," he said, predicting that senior Democrats will unleash serious pressure soon for them to declare an allegiance. Tuesday's outcome could prove a setback for Clinton's push for a suspending the federal gasoline tax for the summer, a proposal she used as proof that she's a champion of the working class.</p><p>"The American people aren't looking for more spin or more gimmicks," Obama told supporters Tuesday night, "but honest answers about the challenges we face."