The war for the White House is being fought on many fronts, and among the fiercest is the battle of the daughters.

In July, Vanessa and Alexandra Kerry boosted their father Senator John Kerry's election chances with a charming performance at the Democratic convention, recounting how their father saved their pet hamster from a watery grave.

Last night it was the turn of President Bush's girls, Jenna and Barbara, to woo the thousands of Republican delegates at the party's convention in New York.

Things did not go well for the 22-year-old Bush twins. Far from making the audience chuckle with warm-hearted tales of family life, they drew disapproving looks for being flippant.

They began badly by criticising their grandmother, Barbara Bush, the wife of former US President George Bush senior. The matriarch forced a smile as the twins complained she was "not very hip".

"We already know she doesn't like some of our clothes, our music, or most of the TV shows we watch. She thinks Sex and the City is something married people do but never talk about," Jenna told an audience which barely stirred.

Nervous laughs came from the twins. Barbara picked up: "Jenna and I are really not very political but we love our dad too much to stand back and watch from the sidelines."

She tried again: "When your dad's a Republican and you go to Yale, you learn to stand up for yourself.

"I knew I wasn't quite ready to be president, but number two sounded pretty good. Who is this man they call Dick Cheney?" she asked to some polite chuckles.

Even their attempts to talk about the closeness of the Bush family fell flat. "You know all those times when you're growing up and your parents embarrass you? Well, this is payback time on live TV," said Jenna.

Barbara went on: "Take this. I know it's hard to believe, but our parents' favourite term of endearment for each other is actually Bushy."

Few who attended would have called it a show-stopping performance, and one political pundit suggested that whoever wrote their speech should be fired.

It was a far cry from the show put on by the Kerry sisters, who showed no nerves and whose performance was praised as one of the convention's highlights.

Alexandra, 30, spoke movingly of the advice given by her father, a Vietnam veteran, when she was a "brooding" 19-year-old.

"My father told me to look outside. He said, 'Ali, this is a beautiful day. Feel the sun. Look at the country you live in'.

"He said, 'I know men your exact age who thought they had the same future you have. Whose families were never born, who never again walked on American soil. They don't feel this sun, Ali. Remember that you are alive. And that you are an American. Those two things make you the luckiest girl in the world'."

And then they told the political anecdote of the election season. Alexandra told how Vanessa's pet hamster Licorice was once knocked off a dock and "bubbled down to a watery doom".

"That might have been the end of the story," she said. "But my dad jumped in, grabbed an oar, fished the cage from the water, hunched over the soggy hamster and began to administer CPR. He was never quite right after that, but Licorice lived. Like I said, it may sound silly. We still laugh about it today. But to us it was serious and that's what mattered to my father," she said to huge applause.

The latest polls show that Mr Bush and Mr Kerry are neck and neck in the race for the White House, but if family support was measured the Kerry girls would be well in the lead.

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