In America, in 1917, the administration grasped, for the first time, that war, like pop-up toasters, was a marketable commodity. Its salesman, Woodrow Wilson, who had run for office on a peace ticket, established a giant propaganda ministry, the US Committee for Public Information. Its mission was to persuade liberal progressives that war chimed with their ideas of a new and rational world order.

'Four-minute men' were recruited as volunteer preachers instructing their communities to shop unpatriotic neighbours as suspected spies. Citizens were warned that America might be renamed New Prussia, while Hollywood was told that no films could be exported without an undertaking to show US propaganda films alongside.

But something more fundamental was happening. According to Stuart Ewen, the social historian of spin, the CPI extinguished the Enlightenment dictum that people were essentially rational. Public opinion was for mobilising and managing. The public mind, Ewen wrote, was now seen as an entity to 'be manufactured, not reasoned with'.

functional rationality? warfare and PR