I found this in Norman Davies’s book Europe: A History. It strikes me as particularly relevant to the election campaign underway in the United States:
Theorists of propaganda have identified five basic rules:
1. The rule of simplification: reducing all data to a simple confrontation between “Good and Bad”, “Friend and Foe”.
2. The rule of disfiguration: discrediting the opposition by crude smears and parodies.
3. The rule of transfusion: manipulating the consensus values of the target audience for one’s own ends.
4. The rule of unanimity: presenting one’s viewpoint as if it were the unanimous opinion of all right-thinking people: drawing the doubting individual into agreement by the appeal of star-performers, by social pressure, and by “psychological contagion”.
5. The rule of orchestration: endlessly repeating the same messages in different variations and combinations.