"When he loves you, there is no sacrifice too great," Alexandra Kerry, 30, said at the Democratic convention. "And when he cares for you, as he cares for this country, there are no surer hands and no wiser heart."
Her sister, Vanessa, 27, struck a similar theme in her own speech. "I've heard people talk about John Kerry, the father, and John Kerry, the public servant, as if they were two people divided. But I can assure you they are truly one and the same," she said. "What drives my father to serve is exactly what has made this public servant the father I'm proud of, look up to and love."

Their remarks, to introduce a film about their father, seemed designed to humanize the Democratic presidential candidate.

Alexandra, for instance, told of the time her father jumped off a dock to pull her younger sister's drowning hamster out of the water. He then saved the animal by administering CPR.

"There are still to this day some reports of mouth-to-mouth. But I admit that's probably a trick of memory," she said to laughs from the audience at the FleetCenter.

Alexandra also told of brooding one day on a ride back to college. She said her father told her, "Ali, this is a beautiful day. Feel the sun. . . . I know men your exact age, who thought they had the future you have, whose families were never born. Who never again walked on American soil. They don't feel this sun."

"Ali," she said her father continued, "remember that you are alive. And that you are an American. Those two things make you the luckiest little girl alive."

The sisters' speeches came at the end of a week of delegation breakfasts, a star-studded "Rock the Vote" youth event and live television interviews on the convention floor.

It was also a week, they said, that the impact of their commitment to their father's campaign for president sunk in.

"To be totally candid, I am scared," Vanessa said at a press breakfast this week. "You want to know you can walk down the street and not have someone give you a kiss on the cheek because they think they can, which has happened to me." She called their immersion into politics "baptism by fire."

Alexandra is a filmmaker who is making a documentary about the campaign and sometimes travels with a cameraman. Vanessa is a student at Harvard Medical School.

They're the only children of Kerry and his first wife, Julia Thorne. The couple divorced in 1988. The daughters lived with their mother. Thorne has remarried.

The sisters were introduced at the convention by their stepbrother, Andre Heinz. Heinz, 34, is the middle of three sons of Teresa Heinz Kerry and the late senator John Heinz of Pennsylvania, who died in an air crash in 1991. Teresa and John Kerry married in 1995.

Andre Heinz is an environmental consultant who has been living in Sweden. And he has the reputation as the comedian of the family. He was joined unannounced on stage by his younger brother, Chris Heinz.

The Kerry sisters said earlier they're having a good time. They work as a team during interviews and at appearances, taking turns answering questions and sometimes helping finish each other's sentences. They often hug or squeeze each other, as if to make sure they're not separated. They joked that if one stumbled on the way to the podium, they'd fall together in solidarity.

As Alexandra stepped forward to give her speech Thursday night, Vanessa held her back a moment to wipe lipstick off her cheek.

Vanessa was usually the more confident of the two during the week, especially when the conversation turns to policy or politics.

Asked if she disagrees with her father on any issues, she said she believes gay marriage should be legal, while her father supports only civil unions.

The sisters defended their stepmother, Heinz Kerry, who made headlines this week when she told a reporter who questioned her about a comment she'd made to "shove it."

"I'm sitting here bristling," Vanessa said when a reporter brought up the subject. "This attempt to make a controversy out of something that isn't. Sorry, I get very passionate.