A lie artfully told with sufficient frequency eventually becomes the truth for the majority of listeners who are then able to recognize the others and either eliminate them or hold them at a distance. Propaganda has always been a tool of politics and religion, but has become a profession in recent history.
Here is the list of propaganda types posited by Henry T. Conserva:
Logical fallacies
Diversion and evasion
Appealing to emotions
Using falsehoods and trickery
Playing on human behavioral tendencies, mental capacities, and processes.
Speaking and/or writing style
Reason or common sense. There is considerable irony employed in this one.
I think it is now a required course in journalism school.