Others, including Robbins, say that Bonesmen deliberately cultivate an aura of mystery around the society to give it greater significance than it deserves. Some critics during this election season have demanded that Kerry and Bush renounce their old association, arguing that membership of a secret society is inimical to the presidency. Conspiracy theorists have long insisted that the world is controlled by a shadowy network of Yale alumni, and the Kerry-Bush contest feeds directly into that fantasy. The rise of the Bonesmen has not gone uncharted.

This is an organisation where members can call up presidents, supreme court judges and cabinet members, and ask for jobs, money and connections,' says Alexandra Robbins, author of Secrets of the Tomb, an exposé of Yale's secret societies. 'Skull and Bones is probably the most successful elite network this country has. That both Kerry and Bush will feature on the presidential ticket next November might be dismissed as weird coincidence, except for the fact that for generations the club's alumni have occupied positions of power and influence in America. The society is open to only 15 students from the senior or graduating class of Yale each year, and it is believed there are fewer than 800 living members.

But even those anointed few - those, for example, who could be trusted with the secret of President Bush's society nickname which was 'Temporary', as he defied convention and failed to choose one - would be staggered at the odds of two Bonesmen turning up in a direct contest for the US presidency.

Skull and bones secrets