"All propaganda must be popular and its intellectual level must be adjusted to the most limited intelligence among those it is addressed to.  No matter what amount of talent is employed in the organisation of propaganda, it will have no result if due account is not taken of these fundamental principles. Propaganda must be limited to a few simple themes and these must be represented again and again. Here, as in innumerable other cases, perseverance is the first and most important condition of success."

Adolph Hitler in Mein Kampf  1925