WASHINGTON - It was a bitter ending for Barack Obama in Pennsylvania, as his protracted presidential fight with the resilient Hillary Rodham Clinton goes on.

Clinton's win Tuesday in the Keystone State, declared by news organizations with less than 10 percent of the vote counted, reinforces prospects that the primaries and caucuses that began in the January cold of Iowa might not be over when the final votes are counted in June.

The next big showdown in the increasingly vitriolic contest for the Democratic nomination is May 6 in Indiana and North Carolina. Polls show Clinton running even with Obama in Indiana, but she trails by double digits in North Carolina.

Democratic Party leaders called "superdelegates" almost certainly will have to decide their party's standard-bearer, and Clinton's victory in Pennsylvania could stem a rush of them to Obama that almost certainly would have ensued had he won.

After losing 11 straight contests to Obama during a brutal February, Clinton has won four of six primaries, including Pennsylvania, Ohio and Texas.

The script has become familiar.

Network exit polls said Clinton's margin of victory was built heavily upon her appeal among white women - which she won by more than 20 percentage points - blue-collar voters, and older voters.

"It is union households, a lot of white women, a majority of white men, Catholics, poorer and less educated voters going for Senator Clinton, and blacks and urban voters and better educated voters for Senator Obama," said Assistant Director Clay F. Richards of the Quinnipiac University Poll, which surveyed extensively in the state. "It is the same breakdown we have seen in Ohio, Texas and New Jersey."

Two weeks ago, Obama seemed to be moving toward a come-from-behind victory in Pennsylvania that would have undermined much of Clinton's rationale for staying in the fight. The Illinois senator had closed a huge gap in the polls to draw even with Clinton, the senator from New York, and was outspending her on television by roughly 2-1.

But Obama's comments about "bitter" small-town Pennsylvanians who "cling" to guns and religion in tough economic times gave critics fodder to declare him an elitist, and his momentum stalled. Exit polls showed a majority of late deciders breaking to Clinton.

Obama still leads in delegates and dollars, but Clinton now can make a more compelling case for her momentum vs. his math. She has begun arguing, apparently with some effect, that she is both better prepared to take on presumptive Republican nominee John McCain in November and take over the presidency in January.

Clinton's victory is tempered by the reality of Obama's money advantage. Obama had $42 million on hand at the beginning of April, Clinton about $9 million, according to their reports to the Federal Election Commission. She also was more than $10 million in debt, effectively making her broke. But her advisers think a Pennsylvania victory will boost her coffers.

To draw even with Obama in delegates, Clinton will have to win about two-thirds of the remaining 404 delegates at stake from now through June 3, when Montana and South Dakota vote. She also will have to keep pace with Obama among superdelegates who declare their allegiance in coming days. The Associated Press' latest tally entering Tuesday had more than 300 uncommitted superdelegates.

Pennsylvania's complicated delegate-selection process could mean that Clinton will still be more than 400 delegates short of the 2,025 needed to win the nomination while Obama likely will be slightly more than 300 delegates short.

Clinton is likely to spend more time in the next two weeks in Indiana than in North Carolina because Indiana has more similar demographics to Pennsylvania, according to her campaign.

She is expected to continue to rely heavily on surrogates such as her husband, who visits rural areas; her daughter, who has visited more than 100 college campuses; and a variety of other friends and acquaintances such as New York farmers and congressional lawmakers.

While Clinton likely won't be able to catch Obama in pledged delegates by the time the primary season ends, he won't be able to cross the 2,025-delegate threshold without help from superdelegates either.

States that remain on the primary calendar after May 6 are relatively cheap media environments. That means Obama's money advantage could be blunted because there is only so much TV air time available in markets like Sioux Falls, S.D.; Billings, Mont.; and Louisville, Ky.

John Brabender, a Republican consultant based in Pittsburgh, said the rough Obama-Clinton fight in Pennsylvania "has taken the shine off both of them" and that Obama was especially affected.

"He was so fresh. It was like going on a first date; you can't do anything wrong," Brabender said. "By the third date, you notice they didn't floss that date. That is the natural course of a campaign."

Brabender also said those who had expected Clinton to succumb to pressure to get out fundamentally misunderstood her.

"Hillary Clinton, in my opinion, has been running for president for 40 years, to some extent," Brabender said. "Why in the world would she say, 'I have another few weeks, I think I'll get out of it.' This is her shot. A lot of people have argued she has earned that right. And it is not like he is pummeling her."

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(Contributing: Brian Tumulty, GNS)

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Contact GNS Political Writer Chuck Raasch at craasch@gns.gannett.com.