WASHINGTON — Hillary Clinton could win the battle but still lose the war.
The New York senator approaches Tuesday's Pennsylvania primary clinging to a small lead in the polls, poised to ride support from whites, women and working-class Democrats to a possible victory over Illinois Sen. Barack Obama.
It may not be enough.
Even with a Pennsylvania win, she'll still trail in delegates and the nationwide popular vote as the Democratic presidential campaign enters the homestretch, a six-week rush that will give voters their last say in who wins the nomination.
By the time voting ends on June 3, more than 25 million Democrats will have voted in most of the country, likely giving a preference but not the nomination to Obama.
Instead, he and Clinton then will go into June fighting for the remaining "superdelegates," the party officials and insiders who get to vote however they choose, regardless of votes in their home states. Superdelegates hold about 20 percent of total convention votes.
The candidates enter this final phase after the longest break from voting of the campaign — it's been six weeks since Mississippi voted on March 11 — in a period of increasingly personal attacks and revelations.
Among the developments since the last voting:
Both likely have been scarred politically — he among working-class whites, she among voters who call her dishonest.
But it's Clinton who has the stronger challenge, needing to overcome Obama.
"She still has a chance to stay in the game," said Linda Fowler, a political scientist at Dartmouth College in New Hampshire, arguing that a strong win Tuesday would give Clinton an argument to keep going.
"But it's not clear that even staying in the game is enough to win the nomination. The arithmetic isn't there."
Heading into Pennsylvania, Obama has 1,648 delegates, needing 377 more to clinch the nomination. Clinton has 1,509, needing 516 more, according to the Associated Press.
After Tuesday, there are just eight primaries — Indiana, North Carolina, West Virginia, Kentucky, Oregon, Puerto Rico, Montana and South Dakota — with 354 delegates at stake.
(Nebraska has a primary on May 13, but its delegates were selected earlier in caucuses.)
Given the way that Democrats allocate delegates, it would take landslides in every state for Clinton to have a chance of gaining significantly on Obama in the delegate count. Even then, it's almost impossible that she could overtake him.
It's also highly unlikely she'll overtake him in the popular vote.
The popular vote is a key indicator for superdelegates who either don't want to buck the popular choice — or see it as a sign of general election strength.
With more than 25 million votes already cast, Obama leads Clinton by an estimated 13.7 million to 12.9 million, a margin of more than 800,000.
So even if Clinton managed to win Pennsylvania by the same 10-point margin she won in Ohio, more than current polls suggest, she'd emerge with only a 200,000-vote margin.
That would leave her still trailing by more than 600,000 votes — with no big states left.
Even if she included the votes from Florida and Michigan — where she won non-binding primaries and neither candidate campaigned — she'd trail in the popular vote by about 4,000.
Still, she could argue that she's fared better among working-class whites in big swing states such as Ohio and Pennsylvania, which are critical to victory in the fall.
"Historically, the people who are most likely to be swing voters are the types Senator Obama has had the most problems with," Clinton strategist Geoff Garin said.
Larry Rasky, a veteran Democratic strategist who worked for Delaware Sen. Joseph Biden in the primaries, agreed that the party risks another general election loss if it can't connect with the kind of ethnic Democrats who deserted to Ronald Reagan in the 1980s.
"Our party's biggest risk is that somehow we lose those Reagan Democrats again," Rasky said.
Clinton's last argument to superdelegates is that she's the more likely winner for the fall campaign against Republican John McCain.
That's based on the facts that Obama hasn't been as fully vetted as she has and could face new and troubling revelations in the months to come, and that he's had trouble winning some parts of the Democratic coalition.
"If he does not win (Pennsylvania) after having outspent us, it will once again raise serious questions among voters and superdelegates whether or not Senator Obama can win the big swing states that any Democrat would have to win in November," Clinton spokesman Howard Wolfson said Monday.
But that assumes that Obama would lose those states in November.
It also assumes that Clinton, conversely, would win swing states in the fall that she lost to Obama in the primaries, such as Iowa, Minnesota, Missouri and Wisconsin.
Neither is a certainty, particularly in a campaign against Arizona Sen. John McCain, who could have crossover appeal to independents and some moderate Democrats.
While a convincing win Tuesday could move the party back in her direction, Clinton is trailing Obama in her party's opinion. According to a recent poll for ABC News and the Washington Post, Democrats now see Obama as the stronger candidate for the fall by a 2-1 margin.