Reason is poor propaganda when opposed by the yammering, unceasing lies of shrewd and evil and self-serving men. The little man has no way to judge and the shoddy lies are more attractively packaged.

Robert A. Heinlein (1907–1988) American writer

Story (1949-12), “Gulf” [Baldwin], Astounding Science Fiction, Vol. 44, No. 4
    (Source)

Collected in Assignment in Eternity (1953).