ROCKY MOUNT, N.C. - At this crucial moment, the Democratic presidential battle is an enigma wrapped in two ironies.

The first: Sen. Hillary Clinton found a compelling voice and a plausible strategy only after she had squandered her chances of winning the nomination without a divisive struggle over superdelegates and convention rules. It took a series of defeats to galvanize her campaign and help her put forward a better self.

The second: Mrs. Clinton's embrace of a gas tax holiday has endowed Sen. Barack Obama with a sense of purpose and a burst of energy at precisely the moment when his battered campaign seemed lethargic and reactive. Standing up to a proposal that even Clinton supporters see as pandering has allowed Mr. Obama to revisit his most successful days as a fresh voice uninhibited by Washington's habits.

The new Mrs. Clinton is a wonder to behold. In the 1990s, Hillary and Bill Clinton were trashed by their enemies as elitist, Ivy League, McGovernite liberals -- i.e., exactly the way Mrs. Clinton's people are eviscerating Mr. Obama.

But over the last month, Mrs. Clinton has emerged as a working-class hero who gets knocked down, always gets up, and thus wins favorable comparisons with Rocky Balboa. The new Hillary would not have been possible if her original front-runner strategy had worked. She could only become the underdog if the voters made her one and could only cast herself as a fighter if she had to fight. Nothing becomes her so much as hardship. That she and Mr. Obama returned on Monday to campaign in North Carolina, a state once viewed as landslide country for Mr. Obama, is a sign that both sides see the hard-luck Hillary on a roll.

Of course Mr. Obama has had a long rough patch, capped by the Rev. Jeremiah Wright's circus of resentment. But Geoffrey Garin, Mrs. Clinton's pollster, argues that Mrs. Clinton had more to do with the turn in the race than she gets credit for. "The change in direction is not just about Obama, it's also about Hillary," he said. "She's become a far more appealing candidate to a far broader range of voters."

She even speaks better. "She used to offer this annoying list of issues," said one well-connected Clinton supporter. "Now, she offers a message and an argument -- that you need a fighter like her to undo all the damage the Republicans have done."

Bill Clinton has learned lessons, too, campaigning as a happy warrior in appreciative country towns. Barbara Allen, the former North Carolina Democratic chair and a Clinton supporter, said the former president's emphasis on "the small places, places people don't normally get to at election time" has squared with Hillary's emphasis on the forgotten voter.

Still, there is a hangover from Mrs. Clinton's overconfident front-runner strategy: Her failure to organize effectively in caucus states and in the primaries after Super Tuesday more than explains Mr. Obama's lead of somewhere between 135 and 140 delegates. Mr. Obama earned a 132-pledged-delegate lead over Mrs. Clinton in the caucus states alone, and netted another 73 in the primaries held two weeks after Super Tuesday. She is in a hole her campaign dug for itself.

But on the campaign trail, things were looking grim for Mr. Obama until Mrs. Clinton joined John McCain, the presumptive Republican nominee, in endorsing the gas tax holiday.

Sure, voters usually back Santa Claus, even if he's only offering 30 cents a day. But by running hard against the temporary tax break as a typical Washington gimmick, Mr. Obama has put substance behind his claim that he'll tell voters what they don't want to hear.

"This focuses on Obama as the truth-teller," said Rep. David Price, one of Mr. Obama's leading North Carolina supporters, "and it sets up a nice contrast with Clinton because of the position she has taken, and ultimately with the straight-talker himself." For the first time in weeks, the old Mr. Obama was back, talking about something other than his former pastor and bitter voters.

The old, inspiring Mr. Obama was clearly capable of beating the old, overconfident Mrs. Clinton. The pugilistic Mrs. Clinton turned the recently listless Mr. Obama into a pushover. But a contest between the old Mr. Obama and the new Mrs. Clinton is a fair fight. It's too bad only a few states are left to see it.