CHICAGO — Weary, divided Democrats looked Wednesday toward Pennsylvania's April 22 primary to help sort out the tense, unpredictable struggle being waged by Hillary Clinton and Barack Obama — a fight that seems likely to continue through spring and perhaps all summer.
On Wednesday, Clinton reveled in having won three of four primaries on Tuesday, launching a comeback for a campaign that even her husband had said could end if she lost Texas and Ohio.
But while she won both those states and Rhode Island, she scored a net gain of only about a dozen convention delegates, leaving her 101 behind Obama. He now has 1,564 delegates to Clinton's 1,463, according to the Associated Press. A total of 2,025 is needed to nominate.
While Obama has the lead, Clinton has the momentum and a strong argument: that she's prevailed in the big, diverse states that the Democratic Party needs to win the White House. That argument could be important if the race ultimately is decided by the 796 party leaders known as superdelegates, who control about 20 percent of the convention's votes.
Superdelegates were created in the early 1980s to balance the sometimes extreme views of party activists with the pragmatic judgment of practical politicians. The goal was to help give the party its best chance to nominate a candidate who could win in November.
While the current superdelegate count favors Clinton, 241 to 202, more than 350 remain undecided. They're all unpledged; any one of them can switch loyalties at any time.
Clinton seemed to be talking directly to those delegates Wednesday.
"New questions are being raised. New challenges are being put to my opponent," she said. "Superdelegates are supposed to take all that information on board, and they are supposed to be exercising the judgment that people would have exercised if this information and challenges had been available several months ago."
Clinton's also suggesting that if she wins Pennsylvania, the superdelegates should consider the breadth of her vote-getting appeal.
The New York senator has won New York, California, New Jersey, Massachusetts and other large states — or as supporter Sen. Charles E. Schumer, D-N.Y., put it Wednesday, "she's won states with 263 electoral votes," seven short of the number needed to win the presidency, with 10 states and two U.S. territories yet to vote.
Pennsylvania, at least on paper, is classic Clinton country.
"If I were Hillary Clinton and I had to pick a big state for my final showdown, I'd pick Pennsylvania," said Clay Richards, who conducts Pennsylvania polls for the Quinnipiac Polling Institute.
"Philadelphia looks a lot like New Jersey," he said, "and by the time you get to Pittsburgh, it looks like Ohio." Clinton won both states.
She also has the support of popular Gov. Ed Rendell, who beat an African-American Republican in 2006 to win a second term. The older voters and union workers who dominate the state resemble groups that have voted in big numbers for Clinton elsewhere, such as Ohio.
But high expectations could be Clinton's undoing.
"If Obama can reverse the trend and win here, he effectively kills her," said David Barker, an associate professor of political science at the University of Pittsburgh.
Obama emphasized his own broad appeal on Wednesday.
"We won twice as many states as Senator Clinton," he said. "We have won decisively in a whole number of states, and Senator Clinton and her campaign have tended to cherry-pick states they think are important."
Pennsylvania, with 158 delegates up for grabs on April 22, is the largest of 12 contests remaining. Wyoming holds caucuses Saturday, and Mississippi has a primary on Tuesday. Obama is a strong favorite to win both contests, which together have 45 delegates.
After Pennsylvania, the spring calendar includes some states now presumed favorable to Obama, notably North Carolina, Montana, Oregon and South Dakota, while demographics may favor Clinton in Indiana, West Virginia and Kentucky.
Should neither candidate push the other out of the race, a huge wild card confronts them: What to do about Michigan and Florida? The two states held primaries in January, defying Democratic Party rules, and the party has refused to recognize the results.
Clinton won both contests, but Obama, in deference to the rules, didn't campaign in either. Clinton now wants their delegates admitted to the convention.
Obama campaign strategist David Axelrod called the matter "an issue for the Democratic National Committee. I'm not going to get into modes of resolution to this. We would like to see Florida and Michigan represented."
First, though, come more primary battles — and shifting tactics.
Clinton blew Obama an air kiss on Wednesday when Harry Smith of CBS told her that "a lot of people in Ohio" said they wouldn't mind a Clinton-Obama ticket.
"Well, that may, you know, be where this is headed," she said, laughing.
Later, in a conference call with reporters, her chief strategist Mark Penn refused to discuss the possibility, saying the campaign is focused only on winning.
Obama, too, wouldn't discuss any ticket: "We are just focused on winning this nomination."
Instead, his camp repeated its demand that Clinton release her tax returns.
"Though her campaign has tried to kick the issue down the road, Democratic voters deserve to know, right now, why it is she is hiding the information in her tax returns from last year," a memo from the Obama campaign said.
Clinton communications director Howard Wolfson said the returns will be available "on or around April 15."
Turning the tables, Wolfson demanded that Obama "release all relevant financial and other information related to indicted political fixer Tony Rezko."
Rezko, a one-time Obama fundraiser whose wife was involved in a land deal with Obama, is facing federal corruption charges in Chicago. Obama has called the land transaction "a boneheaded move" and said he's been forthcoming about the relationship. The Clinton camp insists that Obama hasn't detailed how much money Rezko raised for him or where it came from.