We are far more used to politicians' offspring embarrassing mum or dad than helping in their election efforts. You could rely on Mark Thatcher or Ronald Reagan Jr to cause headaches for their parent's PR advisers, not do their jobs for them.
Yet 24-year-old Meghan McCain has done just that, eulogising her father in an illustrated children's book called My Dad, John McCain Aimed at five- to 10-year-olds, it chronicles the presidential hopeful's struggles as a student and his heroics as a prisoner of war in Vietnam.
It's easy for us Brits to assume that such sentimental spin will backfire but, having lived in the US for three years, I can assure you that Americans are made of gooier stuff. There, a commitment to "family values" isn't seen as a devalued political soundbite but the sine qua non of a politician's suitability for office.
But the McCain book takes matters one step further and springs, I suspect, less from a daughter's blind love for her father than some strategist's cynical desire to simplify the campaign's line. I suspect that the real target readership isn't America's primary school kids but their parents, who will buy it for their kids but read it themselves. At the very least they will see it featured on TV and make the association, "Well, his daughter loves him so he must be a good man."
It may be cynical but it will, probably, win votes in what could be a very close election. The problem with raising the profile of a politician's child, though, is keeping them on message. If Meghan McCain strays from her syrupy fairytales between now and November 4, the media will have a field day, and the happy ending envisaged by the architects of her book may never materialise.