It is hardly uncommon for politicians to lie, especially when their careers are threatened by a sexual transgression — John Profumo about Christine Keeler, for example, and Bill Clinton on not having had ‘sexual relations with that woman, Miss Lewinsky’. But there is a particular kind of distortion of the truth that is rare over here but almost routine among American presidential candidates; and this is the way they embellish their personal histories to maximise their appeal to voters. It’s been going on for ages among candidates of both main parties, but presently most scrutiny is directed at Ben Carson, the retired neurosurgeon and Seventh-day Adventist — denier of global warming, Darwinism and most other fashionable creeds — who has surprisingly jumped in the polls to the front of the Republican field.

Carson’s story is one of rags to riches in which a violent temper as a boy was cured by study of the Bible. But none of his school contemporaries remember this violence, especially an incident in which he says he tried to stab a young friend. They all remember him as a peaceful young chap. His life, as described in campaign speeches, is more turbulent than anyone else can recall, and his boasted achievements and triumphs in adversity have proven impossible to verify. In particular, his claim to have been offered a scholarship to the United States Military Academy at West Point has been proven unfounded.

Then there is Ted Cruz, the Hispanic senator from Texas and another Republican candidate, whose campaign speeches have been much enriched by his vivid descriptions of the exploits of his Cuban-born father — now 76 and a US citizen — during the Castro revolution in the 1950s against the dictator, Fulgencio Batista. These portray his father, Rafael Cruz, as a rebel leader, bomb-thrower, gun-runner and so on, whereas diligent research by the American media has found little evidence of this. His former Cuban comrades and friends describe him as little more than a rebellious teenager who wrote on walls and marched in the streets.

Donald Trump, whose position at the top of the polls was — to his fury — usurped by Carson, is the author of countless questionable statements, but the main one to have been challenged is the extent of the wealth of which he constantly boasts. There is no question that he is extremely rich, but he talks about being worth more than ten billion dollars whereas Bloomberg, for example, says about three billion. This might not seem to matter very much, but Trump rests his case for election on his unique skills as a deal-maker that have made him, in his view, quite exceptionally rich.

Even Hillary Clinton, the favourite for the Democratic nomination, can be economical with the truth. During her last bid for the presidency, in which she was beaten by Barack Obama, she was forced to retract a claim that in 1996, as First Lady, she had landed at an airport in Bosnia under sniper fire. ‘There was supposed to be some kind of a greeting ceremony at the airport, but instead we just ran with our heads down to get into the vehicles to get to our base,’ she said. A video, however, showed her ambling with her daughter Chelsea across the airport tarmac, smiling and greeting well-wishers. There had been no sniper fire. In another perplexing statement, Hillary said she had been named after Sir Edmund Hillary, the New Zealand mountaineer who conquered Everest, whereas in fact she was already nearly six years old when Sir Edmund reached the summit in 1953.

You might expect presidential candidates to be more careful after what happened to Vice-President Joe Biden in 1988. He was then seeking the Democratic nomination but was forced to withdraw from the race after he made a speech about his rise from humble roots to become the first member of his family ever to attend college. But his fall from grace was not due to the fact that this statement wasn’t true, which it wasn’t, but because his remarks had been lifted almost verbatim from a campaign speech in Britain by Neil Kinnock when he was leader of the Labour party. Biden even included Kinnock’s statement that his ancestors were coal miners, which wasn’t true of Biden either, though it was of Kinnock. Plagiarism is regarded in America as an unpardonable offence; inventing a life story isn’t. The people just love fairy tales.