What do you do if you've won a sensational victory in a Republican primary, unseating the establishment favourite, but the media just won't let go of past indiscretions such as your youthful dabbling in witchcraft and belief that masturbation is a form of adultery?

Well, if you're Christine O'Donnell, you turn to an advertising guru called Fred Davis, a veteran of many past Republican races, and you get him to make you a 30-second TV advert. The new slot has O'Donnell speaking to camera with a large, homely smile on her face.

"I'm not a witch," she says, which as an opening line to a political advert is pretty grabby. "I'm nothing you've heard. I'm you."

A tinkling piano plays in the background and the lighting is soft and welcoming. It has the feel of one of those washing-up liquid ads from the 1970s.

It ends with a repeat of the line that looks set to become O'Donnell's mantra as she fights Democratic candidate Chris Coons for a Delaware senate seat on 2 November: "I'm you." All very cuddly for Davis, whose last big political ad was for John McCain in the 2008 presidential race. It labelled Barack Obama the "biggest celebrity in the world" over footage of Paris Hilton and Britney Spears.