Washington Hillary Clinton won't catch Barack Obama in the race for Democratic delegates chosen in primaries and caucuses, even if she wins every remaining contest.
But Obama cannot win the nomination with just his pledged primary and caucus delegates either, according to an analysis by The Associated Press.
That sets the stage for a pitched battle for support among "superdelegates," the party and elected officials who automatically attend the convention and can support whomever they choose.
Two months into the voting, Obama can claim the most delegates chosen by voters.
Clinton can claim victories in most of the big states.
What should a superdelegate do? Unsurprisingly, the two campaigns have different takes on that question.
"It is very difficult to see any scenario that Hillary Clinton would get the nomination in a way that doesn't rip the party apart," said Wisconsin Gov. Jim Doyle, an Obama supporter. "I think that it would be a terrible mistake for the Democrats to not accept the will of the people who have turned out in primaries and caucuses."
Clinton spokesman Doug Hattaway said Obama's lead in pledged delegates is "hardly a mandate."
"Some superdelegates will go with (the) pledged delegate count, but many will go with the candidate they think can win," Hattaway said. "We have a very compelling case to make on that front, given that we're winning general election swing states, must-win states and must-win constituencies."
Clinton won three out of four primaries this week, giving her campaign a much-needed boost after a month of defeats.
But she picked up only 12 more delegates than Obama, leaving him with a 140-delegate lead among those won in primaries and caucuses. Only 614 delegates are available in the remaining contests, meaning Clinton would have to win about
62 percent of them to overtake Obama, according to the AP analysis.
That's nearly impossible, given the way Democrats award delegates proportionally.
Consider this: Clinton posted a big win in the Ohio primary Tuesday, beating Obama by about 10 percentage points. Her take: nine more delegates than him in the Buckeye State.
In the Texas primary, Clinton's margin of victory was smaller, about 3 percentage points, and her net gain was smaller, too: four more delegates than Obama. Obama would wipe out most of that advantage if early returns showing him winning in the Texas caucuses hold up. Final results won't be available until the party's county conventions at the end of month.
The message to be taken from Clinton's victories, again, depends on which campaign is doing the spinning.
"In order to have a plausible path to the nomination, they needed to score huge delegate victories and cut into our lead," Obama campaign manager David Plouffe said in an e-mail to supporters. "They failed."
Clinton's campaign pointed to her earlier victories in states like New Jersey, New York and California, and they questioned why Obama couldn't win in Texas and Ohio on Tuesday.
"We think she can bring Ohio in a general election," said Harold Ickes, a chief strategist for Clinton. "We are not sure (Obama) can do that."
The biggest remaining primary is in Pennsylvania, which will have 158 delegates at stake on April 22.
Clinton's team is optimistic about her chances there. She'll be campaigning hard in the state, as will Ed Rendell, Pennsylvania's popular governor, who is an enthusiastic supporter.
Obama is expected to win the Wyoming caucuses Saturday and the Mississippi primary next Tuesday, but Clinton is competing in both states to hold down his delegate accumulation.
Her advisers acknowledge their past system of focusing on certain states and largely ignoring others - particularly those holding caucuses - was a mistake and helped Obama build a significant lead among pledged delegates.
In the overall race for the nomination, Obama has 1,568 delegates, to 1,462 for Clinton, according to the latest AP tally.