Hillary Clinton and Barack Obama entered the final phase of an increasingly nasty US presidential fight on Wednesday, with Clinton saying her decisive Pennsylvania win proved she was the best candidate to lead the Democrats back to the White House.
Clinton's victory boosted her depleted bank account and gave new hope to her struggling campaign, but the New York senator still faced a nearly impossible task trying to overcome Obama's lead in pledged delegates who will help pick the Democratic presidential nominee at the party's convention in August.
Clinton said Obama's failure to knock her out of the race, despite outspending her in Pennsylvania more than 2-to-1, cast doubt on his ability to capture the big states Democrats need in November's election race against Republican John McCain.
"I've won the states we have to win -- Ohio, now Pennsylvania," Clinton told CNN. "If you look at the broad base of support that I have accumulated, it really is the foundation on which we build our victory come the fall."
Both Democratic candidates looked to the next round of contests on May 6 in North Carolina, where Obama is favored, and Indiana, which is considered a toss-up. The two states have a combined 187 delegates at stake.
Obama said he would battle through the final nine contests ending on June 3 and then make his case to the party's undecided superdelegates who are likely to decide the Democratic presidential nominee.
"Once we have I think a pretty strong case to make that we've won more delegates, we've won more states, we've won more votes, then it will be apparent that we'll be in the strongest position to win in November," the Illinois senator told reporters in New Albany, Indiana.
With more than 99 percent of the vote counted, Clinton led Obama in Pennsylvania 54.6 percent to 45.4 percent, the state's elections division said.
The win paid immediate financial dividends for Clinton, who by midday had raised $5 million since the polls closed on Tuesday and was aiming for another $5 million more by the end of the day, aides said. Clinton's campaign had more than $10 million in debts at the end of March.
"I would welcome a contribution because we are being outspent," Clinton told supporters in Indianapolis. "It's a tremendous challenge to get your message out when you're being outspent in that way."
Obama holds delegate lead
An MSNBC count showed Clinton sliced Obama's national delegate lead by nine in Pennsylvania. Obama now has 1,726 delegates to Clinton's 1,593, short of the 2,024 needed to clinch the nomination.
Neither candidate can win without help from superdelegates -- nearly 800 party insiders who are free to support either Obama or Clinton. Obama campaign manager David Plouffe said he expected those superdelegates to move toward the winner and end the nomination fight sometime after June 3.
"You're going to see the superdelegates make a decision shortly after that," he said.
Clinton hopes a strong run through the last contests brings her closer in delegates won and votes cast and convinces those superdelegates she is the Democrat who can beat McCain.
Both candidates picked up new superdelegate support on Wednesday, with U.S. Rep. John Tanner of Tennessee backing Clinton and Oklahoma Gov. Brad Henry supporting Obama.
Democrats have become increasingly worried about the negative tone of the race, and exit polls showed Pennsylvania voters shared the concern.
About two-thirds of Pennsylvania voters thought Clinton unfairly attacked Obama, while about half thought Obama had unfairly attacked Clinton, the polls showed.
But Clinton won 58 percent of those who decided in the last week, when Obama was on the defensive in a debate over a series of campaign controversies and Clinton questioned his toughness in an ad featuring images of al Qaeda leader Osama bin Laden.
"I know that people like to talk tough and use a lot of rhetoric about fighting and obliterating and all that stuff," Obama said. "I've always believed that if you're tough you don't have to talk about it."
The North Carolina Republican Party launched an ad in the state criticizing Obama and his controversial former pastor, the Rev. Jeremiah Wright, who has come under fire for inflammatory views including saying the U.S. government spread the AIDS virus to blacks.
McCain asked the state party to withdraw the ad, which also criticized Democratic North Carolina candidates for governor Beverly Perdue and Richard Moore for their endorsements of Obama and called him "too extreme for North Carolina."
Obama and Clinton both campaigned in Indiana on Wednesday before heading back to Washington for a Senate vote.
(Additional reporting by Donna Smith, Andy Sullivan, Caren Bohan and David Morgan; Editing by David Wiessler)