By Sandra Sobieraj Westfall
January 14, 2008 12:00 PM

It’s 2 p.m. On the dot. The campaign theme song “Taking Care of Business” throbs down the backstage corridor of the Vinton, Iowa, high school where some 500 Hawkeye Staters have assembled to take their measure of Hillary Clinton. “Let’s go!” shouts the candidate, and she, her aides and Secret Service agents take off in a purposeful march toward the stage entrance. Three steps back, with her long, shiny curls swishing to and fro, Chelsea Clinton, 27, is skipping. Skipping. Says her mom: “She’s my greatest joy.”

She’s even more than that. For the famously intense U.S. Senator from New York and former First Lady, having Chelsea on the campaign trail in recent weeks has provided both a valuable sounding board and solace during an increasingly tight race to become the Democratic presidential nominee. With Chelsea at her side, Clinton, 60, tells PEOPLE, “I feel like I can get in the car and just kick back.” Even on the long drives through rural Iowa before the Jan. 3 caucuses, Clinton could set aside her briefing book and daydream with her daughter about the family vacation they hope to take “when it’s all over”—win or lose.

Although Clinton has put a positive spin on the race—she doesn’t say “if” I win, only “when”—she was no longer the clear frontrunner by the time the voting began. So perhaps it’s no accident that in December Chelsea took time off from her job as an analyst for a Manhattan hedge fund and, along with her grandmother Dorothy Rodham, 88, volunteered to join her mom, warmly rounding out the family portrait. “Chelsea could clear her calendar during December,” says Clinton. “Good timing for me, because that’s when people start paying attention.”

Chelsea’s appearance on the trail is just that—an appearance. She stands onstage, sometimes leaning in to whisper something to her mother, but makes no public remarks and is so adamant about not speaking to reporters that she rebuffed an Iowa fourth grader reporting for Scholastic News. “I’m sorry, I don’t talk to the press,” she told the girl. “Even though I think you’re cute.” But Chelsea is often the last of her mother’s entourage to leave a rally, indulging every autograph request and exhorting quietly up and down the rope line, “I hope you’ll support my mother.” The candidate also bounces ideas off her daughter. “She’s my greatest source of support next to my husband,” she says. “She’s incredibly smart, got great people skills … and lots of good feedback.” And a sense of style that has her kicking across icy sidewalks in high heels.

Pausing for a mug of hot tea in Traer, Iowa, Clinton herself is in sensible, flat-heeled snow boots and the kind of signature pantsuit she favors, she says, for practical reasons: “You never know when you’re going to be walking up stairs with people with cameras down below.” She laughs about counting on Chelsea to keep her from making a fashion faux pas—or even a mess in the kitchen. “The fashion gene skipped a generation,” Clinton admits, “along with the cooking gene.” Chelsea is so accomplished in the kitchen that she boasts not one, but two recipes for tasty Brussels sprouts: one with walnuts, another with brown sugar. “I’m incredibly proud and grateful for the young woman she’s become,” says Clinton.

The spotlight has sometimes been cruel to both mother and daughter, but Clinton says she’s learned to tune out the static, which lately included a screed by Rush Limbaugh about her wrinkles. While she admits to practicing—and getting better at—putting on makeup, she says she’d never try plastic surgery. “I’d be scared to death something could go wrong.”

For now Clinton is focused on being the last Democrat standing after the flurry of primaries this month. And she and Chelsea, trading e-mail by BlackBerry whenever they’re not together, dare not pick a destination for that dreamed-of vacation. Says Clinton, who at dinnertime still has two towns, six hours and 159 miles standing between her and bedtime: “We’re postponing any decisions until a vacation is more real than it is now.”