THE United States allowed members of Osama bin Laden’s family to jet out of the US in the immediate aftermath of September 11, even as American airspace was closed.

Former White House counter-terrorism tsar Richard Clarke said the Bush administration sanctioned the repatriation of about 140 high-ranking Saudi Arabians, including relatives of the al-Qaida chief.

"Somebody brought to us for approval the decision to let an aeroplane filled with Saudis, including members of the Bin Laden family, leave the country," he said.

Mr Clarke said he checked with FBI officials, who gave the go ahead. "So I said: ‘Fine, let it happen.’"

George W. Bush has a forthright speaking style which convinces many people that he's telling the truth even when he's lying. But in under three years, Bush has told at least as many impressive untruths as each of his three predecessors. (See The Mendacity Index , p.27) His style of deception is also unique. When Reagan said he didn't trade arms for hostages, or Clinton insisted he didn't have sex with "that woman," the falsity of the claims was readily provable--by an Oliver North memo or a stained blue dress. Bush and his administration, however, specialize in a particular form of deception: The confidently expressed, but currently undisprovable assertion.

This summer, after it became clear that President George W. Bush had made false statements about Iraq's nuclear weapons capacity and links to al Qaeda in his January State of the Union address, some commentators accused him of being the most dishonest president in recent American history. There has been, however, no scientifically serious attempt to test such accusations--until now.

To come up with our Mendacity Index, we asked a nominating committee* of noted journalists and pundits to pick the most serious fibs, deceptions, and untruths spoken by each of the four most recent presidents. We selected the top six for each commander-in-chief, then presented the list to a panel of judges** with longtime experience in Washington. Panel members were instructed to rate each deception on a scale of 1 (least serious) to 5 (most serious). Then we averaged the scores for each deception and for each president. We believe their validity rests somewhere between the Periodic Table and the U.S. News & World Report college rankings.

This month, the General Accounting Office (GAO) - the investigative and auditing arm of Congress - issued a report that contains some startling revelations. Though they are couched in very polite language, they are bombshells nonetheless.