WASHINGTON (AP) -- After a spellbinding 14-month Democratic nominating contest, voters in four states Tuesday were deciding whether Barack Obama would be the party's standard bearer or if Hillary Rodham Clinton can keep her candidacy alive.
A primary season notable for its prediction-defying twists and turns lurched into new territory yet again, with primaries in Ohio, Texas, Rhode Island and Vermont set to test Obama's momentum and organizational muscle against Clinton's gamble that Democrats were not yet ready to dismiss her pioneering candidacy.
Tiny Vermont, as expected, delivering a whopping victory to Obama, while the vote in Ohio was too close to call.
Exit polls taken for The Associated Press in Vermont showed the Illinois senator winning handily among all demographic groups, including white women and lower-income voters who have long been Clinton's base.
But in Ohio, Clinton was looking strong among her base voters including whites of both sexes, older and less-educated voters, and union members. Obama, who is running to be the first black president, was winning nearly all the black vote as well as younger and more affluent voters.
In interviews Tuesday, Clinton said she would make no decisions about the future of her campaign until after the latest votes were counted.
"I'm not going to think about what comes after until we know what happened today. This is a long journey," she said on the CBS Evening News.
But after 11 straight losses to Obama since Feb. 5 - most by staggering margins - few could envision a plausible path for her to press on without solid victories in Ohio and Texas. Bill Clinton, his wife's most prominent booster and surrogate, said as much last week.
"If she wins both, I think her campaign goes on - she can reasonably claim that she's won the largest and most diverse states in the country," said Andrew Polsky, a political science professor at New York's Hunter College. "If she loses both, I think she drops out. And if it's a split outcome, she has to make a decision about whether to continue. She has shown a real determination to stay with it past the point where a lot of candidates would say 'Enough already.'"
Indeed, Clinton has remained remarkably resilient in the face of steep odds and a host of small and big humiliations, such as the defection of several "superdelegates," including her most prominent black supporter, Georgia Rep. John Lewis.
Buoyed by the sudden influx of small donors who contributed an eye-popping $35 million to her campaign in February, Clinton has kept up a relentless pace on the campaign trail while sharpening her criticism of Obama as being ill-prepared to serve as commander in chief.
Obama, for his part, has been forced onto the defensive over his relationship with a former political patron, Tony Rezko, who went on trial Monday in Chicago on several felony fraud charges. The Illinois senator also faced grilling over whether a senior economic adviser told a representative of the Canadian government that Obama's recent tough talk on NAFTA was nothing more than political theatrics.
Clinton and her campaign team have even forced some public soul searching among the national media, after bitterly complaining that fawning press coverage has helped drive Obama's success.
But at her core, Clinton is a realist and most observers - even those sympathetic to her quest - said she would be loath to wage a fruitless battle if the results are anything less than a decisive game-changer that stops Obama's momentum. Many leading Democrats have also begun publicly expressing concern that a protracted nominating contest will divide the party and strengthen Republican chances in the general election.
But Jennifer Palmieri, a Democratic strategist who worked in the Clinton White House, said if the campaign does carry on through the next major primary in Pennsylvania on April 22 it could actually help the eventual nominee.
"I think continuing on for six more weeks could be good for the process," Palmieri said. "The nominee - who I still think will probably be Barack Obama - will come out much tougher."
Palmieri, a former strategist for John Edwards, added that it would be hard for Clinton to quit the race even if she won just one of the big states Tuesday.
"I find it hard to imagine that Hillary Clinton is going to win Ohio and drop out the next day," she said. "Even though there's been a lot of speculation that she needs to win both, I think it's very hard to win Ohio and walk away, particularly given how much they've invested in it and everything the Clintons have been through."
EDITOR'S NOTE - Beth Fouhy covers presidential politics for The Associated Press.