If there is a single event since the end of the Second World War that has seriously punctured America's sense of confident invulnerability it is, surely, not the withdrawal from Vietnam—that could always be explained away as a masterful reassessment of the nature of the communist threat—but the taking of American hostages by Islamic fundamentalists in Teheran in 1979. That event, more than any other, showed that America's faith in modernization, foreign aid, and a gradual injection of political liberalism as a means of drawing nations into the western orbit rested on brittle foundations. Until the Shah's overthrow Iran had seemed the perfect ally; despite the anti-libertarian blemishes of the Shah's regime, Iran had a prosperous middle class, a formidable standing in the region, a sound economy based on expensive oil, and was emerging from what was thought to be the constricting effect of Islam.