A win's a win, but what's enough? And perhaps more importantly, will anything be enough?

Those are some of the tough questions that face Hillary Rodham Clinton, and to a lesser degree Barack Obama, as they jockey for position and the Democratic presidential nomination in the final two weeks before Pennsylvania's April 22 primary.

Pennsylvania was supposed to be "Clinton Country." Just a couple weeks ago supporters boasted that Clinton was unbeatable. But as a new Quinnipiac University poll shows the contest narrowed to 6 percentage points, it's looking like Pennsylvania could be Clinton's last stand.

"She's getting dangerously close to the edge to losing this," said Clay F. Richards, assistant director of the Quinnipiac University Polling Institute. "It is a game of horseshoes, and close for Obama is a victory for him."

Pennsylvania is the "make it or break it point for the Clinton campaign," he said.

Clinton, who once led by a 16- to 20-point margin, has watched as Obama cut her advantage to 6 points — 50 percent to 44 percent — in the Quinnipiac poll of 1,340 likely Pennsylvania Democratic voters.

Across just about every demographic — old, young, blacks, whites, women, men, rich, poor and in Democrat-rich regions such as southeastern Pennsylvania and Philadelphia, Clinton's numbers are slipping.

At the same time, Obama has played his own expectations game as he constantly reminded voters that he's the underdog during a recent campaign swing through Pennsylvania.

"We don't have great expectations of a victory there and we've stated that from the start," Steve Hildebrand, Obama's deputy campaign manager, told reporters Tuesday.

"We'd love to be even, or even ahead, but the fact of the matter is we still have substantial deficits in the state and we are looking to close it," he said.

After wins in Ohio, Rhode Island and the popular vote in Texas breathed new life into her campaign, Pennsylvania was expected to provide a big victory for Clinton.

Instead, it's becoming the latest must-win state for her.

"She's got to put a stop to the slide and she's got to convince white women especially that it's time for a woman and she's not out of the race," said Richards.

One bright spot for Clinton is that while Obama's standing has improved as Pennsylvania Democrats have gotten to know him, their views of her have remained fairly consistent.

For Clinton, added Richards, the Pennsylvania race comes down to one of perception. She has to persuade voters, and especially undecided superdelegates and donors, that she remains a viable candidate.

Even then, it may be too late, said Charlie Cook, political analyst and publisher of The Cook Political Report.

Clinton needs to win every remaining state with performances well in excess of 63 percent in order to meaningfully close Obama's delegate gap.

Even then, it would be a tall order to convince superdelegates to break a "tie" in her favor, he said.

"It is not mathematically possible for Clinton to get anywhere close to the needed number to win the nomination," he said.

Don't count out Clinton yet, say supporters, including Pennsylvania Gov. Ed Rendell.

"I think she'll close well and get most of the undecideds," Rendell said, predicting a 4- to 9-point win in Pennsylvania.

The narrowing race is no surprise given Obama's financial advantage. The Illinois senator's campaign raised $40 million in March compared to $20 million by Clinton.

Obama's campaign has spent $3.6 million on television ads in Pennsylvania compared to $1.3 million by Clinton's campaign, according to TNS Media Intelligence/Campaign Media Analysis Group, which tracks ad spending.