Jacques Ellul

Propaganda tends to make the individual live in a separate world; he must not have outside points of reference. He must not be allowed a moment of meditation or reflection in which to see himself vis-à-vis the propagandist, as happens when the propaganda is not continuous. At that moment the individual emerges from the grip of propaganda. Instead, successful propaganda will occupy every moment of the individual's life: through posters and loudspeakers when he is out walking, through radio and newspapers at home, through meetings and movies in the evening. The individual must not be allowed to recover, to collect himself, to remain untouched by propaganda during any relatively long period, for propaganda is not the touch of the magic wand. It is based on slow, constant impregnation. It creates convictions and compliance through imperceptible influences that are effective only by continuous repetition. It must create a complete environment for the Individual, one from which he never emerges. And to prevent him from finding external points of reference, it protects him by censoring everything that might come in from the outside.
-Jacques Ellul, Propaganda
source