Formerly the rulers were the leaders. They laid out the course of history, by the simple process of doing what they wanted. And if nowadays the successors of the rulers, those whose position or ability gives them power, can no longer do what they want without the approval of the masses, they find in propaganda a tool which is increasingly powerful in gaining that approval. Therefore, propaganda is here to stay.
It was, of course, the astounding success of propaganda during the war that opened the eyes of the intelligent few in all departments of life to the possibilities of regimenting the public mind. The American government and numerous patriotic agencies developed a technique which, to most persons accustomed to bidding for public acceptance, was new. They not only appealed to the individual by means of every approach-visual, graphic, and auditory-to support the national endeavor, but they also secured the cooperation of the key men in every group -persons whose mere word carried authority to hundreds or thousands or hundreds of thousands of followers. They thus automatically gained the support of fraternal, religious, commercial, patriotic, social and local groups whose members took their opinions from their accustomed leaders and spokesmen, or from the periodical publications which they were accustomed to read and believe. At the same time, the manipulators of patriotic opinion made use of the mental cliches and the emotional habits of the public to produce mass reactions against the alleged atrocities, the terror and the tyranny of the enemy. It was only natural, after the war ended, that intelligent persons should ask themselves whether it was not possible to apply a similar technique to the problems of peace.
(Propaganda - Edward Bernays, 1928, Liverlight, first edition, Chapter II - The new Propaganda)
Gut, Propaganda hat natürlich wieder niemand entdeckt.