Imagine the stink that would erupt were David Cameron to stand up in front of a dinner of rich Conservative backers and make a “joke” that implied that Sarah Brown had had a lesbian affair with Jacqui Smith and produced a love child (and an ugly one to boot). Can you imagine British papers deciding to downplay the story because it was in such bad taste, allowing Cameron to carry on with his assault on Downing Street?

Cross the pond and that is exactly what happened to John McCain at a fundraising dinner in Arizona a decade ago. “Do you know why Chelsea Clinton is so ugly?” he told a handful of big Republican funders. “Because Janet Reno is her father.”

The remark packed into its 15 words several layers of misogyny. It disparaged the looks of Chelsea, then 18 and barely out of high school; it portrayed Reno as a man at a time when she was serving as the first female US attorney general; and it implied that Hillary Clinton was engaged in a lesbian affair while the Monica Lewinsky scandal was blazing. Not bad going, Senator McCain.

Any one of those elements would seem potentially terminal for a public figure. Yet here he is 10 years later presenting himself as a champion of feminism by appointing Sarah Palin as his running mate.

The puzzle is explained partly by the US press, which barely reported the story. The Washington Post broke it in June 1998 but declined to relate the joke on the grounds it was “too vile to repeat”. Such coyness has long been ingrained in the US media, which has an annoying tendency to regard its readers as wayward children in need of moral protection. That’s one important reason, incidentally, that blogs are doing so well in the US - they have no such scruples and behave in ways more akin to the British than the mainstream American media.

Think of presidential candidate John Edwards’ affair and alleged love child. The refusal of most newspapers to touch the story was ridiculed in the blogosphere for weeks before Edwards himself “legitimised” it by confessing.

After his misogynist joke, McCain said sorry to Bill Clinton (though he made no direct apology to the three women involved) and the incident was all but forgotten. Should he win on November 4, his friends in the press might have some answering to do.