Sen. Hillary Rodham Clinton won a clear victory over Sen. Barack Obama in the Pennsylvania primary last night, giving her new hope of sustaining a come-from-behind struggle to become the first woman to win a major party's presidential nomination.

"Some people counted me out and said to drop out," a gleeful Mrs. Clinton told cheering supporters in a Philadelphia hotel. "The American people don't quit, and they deserve president who doesn't quit either.''

The election night locales chosen by the candidates suggested their expectations for the results. Mrs. Clinton, who had been leading in late polls, reveled in her Pennsylvania victory with the voters who gave it to her.

Mr. Obama was on to the Indiana, the site of one of the next battles in the protracted struggle between candidates with different claims to historic precedent as a presidential nominee.

Hours before the New York senator claimed her victory, the two Democratic camps were already competing to impose their contrasting analyses of a race in which Mr. Obama's significant spending advantage allowed him to close but not overcome the double-digit lead that she held when the battle began.

After losing eleven contests in a row, Mrs. Clinton, with no margin for error, managed to win the popular vote in three big states in a row -- Texas, Ohio and, now Pennsylvania -- to buttress her argument to party leaders that she is the more electable candidate in the fall.

Now the race moves on to Indiana and North Carolina, where the balloting will take place in two weeks. But in those contests, Mr. Obama retains the major financial advantage that allowed him to set a presidential primary spending record. Mrs. Clinton, whose campaign was in the red at the end of March, implicitly acknowledged her financial straits in her victory speech as she directed supporters and contributors to her Web site.

Despite his Pennsylvania setback, Mr. Obama maintains a significant lead in the number of delegates elected in primaries and caucuses. It was not immediately clear how many new delegates Mrs. Clinton would net from her Pennsylvania victory.

Although her margin was clear, and would be considered a near landslide in an ordinary election, it seemed to have fallen short of the overwhelming blow-out she needed to dramatically reduce the delegate gap between her and Mr. Obama.

A preliminary tabulation of the Pennsylvania results by the Associated Press showed Mrs. Clinton gaining at least 52 national convention delegates to 46 for Mr. Obama, with 60 still to be awarded. That left Mr. Obama with 1,694.5 delegates, and Mrs. Clinton with 1,561.5, according to the AP tally, with 2,025 needed for nomination.

That leaves, for both candidates, the challenge of making their case to the party officials known as superdelegates. Neither one can reach a nominating majority without their support in Denver.

Mrs. Clinton appeared to be on her way toward carrying the vast majority of the state's counties and congressional districts. Mr. Obama, as expected, carried Philadelphia easily, while Mrs. Clinton followed expectations in winning across the west and center of the state.

Allegheny County had appeared to be Mr. Obama's most likely source of strength in the southwest, but the New York senator carried it easily. She locked up her victory in the southeastern counties outside Philadelphia, where demographics and tide of new voter registrations offered targets of opportunity for the Obama campaign.

Mrs. Clinton was running well ahead in the Lehigh Valley and battling Mr. Obama at least evenly in the crucial suburban counties ringing Philadelphia. With returns still incomplete, Mrs. Clinton was winning Bucks County handily and running neck-and-neck in Montgomery and Delaware counties.

Exit polls conducted for the Associated Press and the television networks showed some familiar demographic fissures. Mrs. Clinton won among females, older voters and whites. Mr. Obama carried men, younger voters, and African-Americans.

Mrs. Clinton's margin among women, 57 percent to 43 percent, was doubly significant in that women accounted for three of every five votes cast in the Democratic primary yesterday. She overwhelmed her opponent among the state's Catholic Democrats. Mrs. Clinton had a narrow lead among Protestant voters; however, a difference that reflects in part the religious preferences of the African-American voters who overwhelmingly backed Mr. Obama.

Mr. Obama won men, 52 percent to 43 percent, according to the exit poll. He won among voters 45 and under while Mrs. Clinton carried older voters in the second oldest state in the nation. Mr. Obama won two-thirds of the voters who were 18 to 29 and more than half of those 30 to 44. Mrs. Clinton had a slight edge among those 45 to 59 and won more than three-fifths of those 60 and older.

Those results were the product of a long race that bruised both candidates. Mr. Obama was on the defensive throughout the campaign. He was rocked by the emergence of videotapes of incendiary, unpatriotic sermons by his onetime minster, the Rev. Jeremiah Wright. He at least partially exorcised the damage from that controversy with a widely praised speech on race and religion delivered at the National Constitution Center in Philadelphia.

Mrs. Clinton was embarrassed by the revelation that a story she had related repeatedly about landing in Bosnia under sniper fire during her husband's administration was false. As videotape of the much more placid reality of her landing was being repeated by on news shows, she sought to throw the spotlight back on Mr. Obama with the observation that she would not have remained in the Rev. Wright's church.

Those topics became fodder for a final debate in Philadelphia in which both candidates, though particularly Mr. Obama, were pressed on those controversies by the ABC moderators.

The primary also featured a proxy war between the state's two highest-ranking Democrats, Gov. Ed Rendell and Sen. Bob Casey, who had faced off in 2002 in a hard-fought Democratic primary for governor.

Mr. Rendell, who was general chairman of the Democratic National Committee during the Bill Clinton administration, led the majority of the state's party hierarchy in backing Mrs. Clinton. Philadelphia's Mayor Michael Nutter joined his predecessor in the Clinton camp, as did other political figures including Allegheny County Executive Dan Onorato and Pittsburgh Mayor Luke Ravenstahl. The support of Mr. Nutter and Mr. Rendell was not enough to stop Mr. Obama in Philadelphia, but may have helped hold down his winning margin, and Mr. Rendell's strong regional popularity may have been a factor in Mrs. Clinton's relatively strong showing in the crucial Philadelphia suburbs.

Mr. Casey's endorsement of Mr. Obama was a major surprise early in the race. The Scranton Democrat put the best face on the results last night, contending that his candidate had made "tremendous progress,'' in an effort that he said had allowed Mr. Obama to "put down a foundation, put down roots in Pennsylvania for the [general] election.''

They campaigned together from then on, but the senator's support was not enough to sway his Lackawanna County neighbors, who ended up strongly favoring Mrs. Clinton, whose father and grandfather, as she repeatedly noted, came from the hard coal region.