As for the second Iraq war, the indignation against Tony Blair festered around the question whether he and his inner court had "sexed up" the "dodgy dossier" in the hope of convincing the public that Saddam Hussein still possessed weapons of mass destruction. Yet even those within the intelligence services who were most angered by the shoddy procedures of Tony Blair and Alastair Campbell, including poor Dr David Kelly, believed that Saddam did possess such weapons, as did the intelligence services of those Western nations such as France, which refused to support Bush and Blair. What Blair's opponents were keenest to prove above all was not that he was a hot-headed warmonger but that he was a liar.

This obsession with humbug is not unique to our times, but it is especially intense just now, and it has been curiously little studied. It is not the least merit of David Runciman's Political Hypocrisy that he shows how our attitude towards this intrinsically tricky subject swings this way and that, never at rest, never blowing in the same direction for very long. This long essay, made up of the Carlyle Lectures he gave in Oxford last year, takes us from the cynics Thomas Hobbes and Bernard Mandeville, via the idealistic American Founding Fathers, then the high-minded Utilitarians and on to the Victorians, who were a curious mixture of humbug and worldly wisdom (Walter Bagehot is a notable omission here); finally to George Orwell's impatience with self-deceiving ideologues. Now and then Runciman pulls in a striking parallel from present-day politics, but for the most part he concentrates his considerable wit and energy on laying out for us exactly what his selected thinkers thought about hypocrisy and how baffling they often found the subject.Not the tough guys in his opening chapters, though. Hypocrisy was no problem for Hobbes. Sovereigns must be prepared to dissemble, cheat and lie if necessary to preserve the peace and security of the state. The ruler puts on the mask of power; he "personates" the Commonwealth. Just as "hypocrisis", putting on a mask, is a term borrowed from the stage, so too is "persona". The whole of politics, as laid out by Hobbes in Leviathan, is one giant act.