It was supposed to be John Kerry's coming-out party. But then Bill Clinton took the stage to introduce the all-but-crowned nominee at a dinner for Democrats in Washington last spring, and delivered a speech so electrifying the crowd nearly forgot Kerry was there. Afterward, at his Georgetown home, Kerry stewed as he packed for a trip. His stepson Chris Heinz, 31, and nephew Jose Ferreira, 35, lounged around Kerry's dressing room offering more than fashion advice. "Clinton had a lot of energy and we didn't," Chris said. "You need to do some simple storytelling that he does so well." Kerry agreed he'd fallen short. "Gosh," he said, shaking his head, "I can do better than that." Chris and Jose kept it coming. Kerry's love of policy, they told him, could be numbing for audiences. And he used a lot of extra clauses and had a bad habit of listing things. Several times Kerry grabbed the phone and called chief political adviser Bob Shrum and campaign manager Mary Beth Cahill, fuming at the way things had gone. Six weeks later Kerry fired his top speechwriter--and has just replaced him with Clinton's old wordsmith, Terry Edmonds.

At the same time that one set of Kerry's kids was setting the candidate straight in private, another was building him up in public. Cute in a chicks vote T shirt, Kerry's daughter Vanessa smacked a campaign sticker onto her bicep and joined the recent abortion-rights march in Washington, D.C. The 27-year-old chatted with Howard Dean and embraced Madeleine Albright. The next minute actress Cybill Shepherd unexpectedly confided, "I was very supportive of Bill Clinton--and you know what? I never had sex with him!" Vanessa deftly sidestepped that land mine. "Congratulations," she deadpanned, then neatly moved on. Later, after a moment with Hillary Clinton--"You guys are doing great, anything I can do," the senator gushed--one of her aides slipped Vanessa a card with Chelsea's phone number on it. "Should we have the fortune to have my father elected, oh, God, I want her on speed dial," Vanessa said.

If Kerry does win, some of the credit will go to the efforts of Vanessa and her extended troupe of siblings. Kids always help make a politician look better. If Chelsea was such a great girl, the thinking went, her embattled parents must have been doing something right. Karenna Gore Schiff spoke with her dad nearly every day when he ran, and often stepped in to speak in his place. But Kerry's kids have taken the role of informal adviser even further. The candidate is surrounded by a brigade of well-spoken, fiercely loyal young family members who seem as determined to win as Kerry is himself. The senator's daughters have joined forces with their "brothers," Teresa Heinz Kerry's sons Chris and Andre. And coming soon to a rally near you: John Edwards's daughter Cate, 22. Add his other kids, Emma Claire, 6, and Jack, 4, and the image is positively Kennedy-esque. The picture of Kerry's "Brady Bunch" family, standing hand in hand alongside Edwards's photogenic brood, is just what the candidate wants to contrast himself with Bush--who speaks often about "values," but whose own kids are known mostly for mischief. When the 22-year-old Bush twins decided they, too, wanted to help their dad campaign, Jenna quickly made the papers--by sticking her tongue out at photographers.

The Kerry kids, older and more assured in public, are now the campaign's most sought-after speakers. "In 1991 I lost my father," Chris Heinz told a Philadelphia audience. "My mother's life shrank. John can do the same thing for the country that he did for our family--bring back the sense of hope and excitement and expansion."

Campaign staffers track media coverage in battleground states and consult "deficit maps" to pinpoint where to send reinforcements. Equipped with briefing papers and their own staff, the kids are deployed like political SWAT teams. Last fall Chris and Vanessa hit college campuses across Iowa. Earlier this month, Vanessa and Alex were dispatched to Wisconsin. Their pull has left some staffers grumbling. "Some of these kids just waltzed in here and expected the campaign to revolve around them because of who they are," says one.

The kids' real talent is portraying the staid candidate as a funny, laid-back guy who doesn't always speak in the dull procedural tones of the Senate. They talk about a dad who seems especially close to all the kids. When his daughters were young, Kerry used to race home to Boston twice a week to see them. He's always been quick with boyfriend advice. Once, when Vanessa was upset over a breakup, she asked her father when men quit lying. He hugged her and said, "50." "So you won't mind if I bring home a 50-year-old?" she said. "OK, maybe 35," Kerry shot back. They'll tease him about his hair, even suggesting he might be thinning up top. Vanessa says, "He freaks out." In public, Kerry is visibly more at ease whenever the kids are around. "They play, which brings humanity to situations," says Teresa Heinz Kerry.

The kids try to maintain their own lives on the side. Vanessa has taken a second leave from Harvard Medical School, where she's in her third year, but still reports to the hospital regularly. "She will literally be running to go speak to a bunch of college kids, and as she's walking out the front door, she's taking off her lab coat," says her roommate Morgan Nickerson, who has to remind her to lose the stethoscope as well. Capable of extreme earnestness--"The other night I had the most incredible conversation with Warren Christopher!"--Vanessa can just as soon laugh at herself: asked if she was starstruck by the former secretary of State, she says, "Totally!" In her backpack she carries Us, People and an EKG textbook. Working a crowd, she possesses all the control her dad has, as well as all of the ease he'd like to have. "You feel her," says Peggy Kerry of her niece. "She makes her father more of a human being by speaking about him."

Alex, 30, who's been content to let Vanessa and Chris handle most of the appearances, is making a documentary about the campaign. A recent graduate of film school, she made a short film that was just shown at Cannes, where she suffered her now infamous encounter with way-too-bright flashbulbs. Though she's also an actress, she's shy and chafes somewhat in the politician's-daughter role. When a man at a house party asked to be photographed with her, after she'd already posed with his squirming teenage son, her face betrayed a flicker of exhaustion. "I enjoy helping my father, but it's weird to think about being on someone's refrigerator," she says. She defers to her little sister on the policy questions, playing off Vanessa's more serious side for laughs. At an event three days before Kerry picked Edwards, a man took Alex aside and asked her to whisper the name of Kerry's choice for veep. "Is it going to be Joe Biden?" he asked. She leaned in dramatically. "Brad Pitt." Ruth Steinbach, 60, was going to vote for Bush until she saw the Kerry girls. "I decided maybe I need to listen to this man." Back in Washington, the deficit map started to twitch.

Teresa's charming son Chris is the natural politician. One of the campaign's top fund-raisers, he's earned the nickname "Pants" inside the family. As in, getting too big for his britches. He's in training for an eventual run himself, perhaps for the congressional seat once held by his father, John Heinz. His 34-year-old brother Andre, an environmental consultant, is best known for cracking up the press corps with his impersonations of Bill Clinton. John, the 37-year-old Heinz brother, is more private. A teacher, he isn't participating in the campaign.

Kerry looks to each of the kids for different things. Harvard Business School grads Chris and nephew Ferreira--often called "the fourth brother"--give advice on strategy and organization. In a Kerry administration, Chris would likely get a post at the State Department, while Jose would be an adviser. This fall Vanessa will go to London to study public health, and she quizzes her dad on the issue. Alex, meanwhile, carefully gauges how he comes across at the podium and on TV. "She's his conscience," says her uncle David Thorne.

The campaign can be hard on all of them. "I hear people saying bad things about my mom on the street," says Chris. For the girls, raised by a mother who fiercely guarded their privacy, watching it now disappear is unsettling. "It has been this sacrifice that I didn't intend to make," says Alex. But they have never been completely anonymous. When Vanessa was a freshman at Yale, a football player who spotted her walking across the quad called out, "You're the f---ing senator's daughter!" But having a friend there who understands, as she, Alex, Chris and Andre do now, makes all the difference. Before she left college she asked Emily Pataki, whose dad is New York Gov. George Pataki, to look out for an incoming freshman named Barbara Bush. Even then, John Kerry's daughter understood that a warm touch goes a long way.