Propaganda is powerful but using it involves risks. It is like a virus or engaging in germ warfare. Once an audience is exposed to a propagandistic message, the only way they can neutralize it is to balance it with an equal but opposite force. Audiences frequently don’t like to think they are being manipulated. If the audience becomes aware of the nature of your propaganda, the equal but opposite force can take the form of a backlash against the author(s) and the propaganda itself. Look at the strong reaction against advertisers who “target” their advertising to specific demographic groups (e.g. African Americans, women, Generation X, etc.), particularly if they are trying to sell liquor, tobacco products, or other items considered “vices” in America.
Once released, propaganda is difficult to control and frequently becomes subject to real world influences. Sometimes propaganda can benefit from real world coincidences: The China Syndrome’s mild propaganda about the dangers of nuclear power plants got a big boost in affecting its audience because of the Three Mile Island incident; the media coverage of the O.J. Simpson murder case may not have tainted potential jurors, but Natural Born Killers’ propaganda against the media’s sensationalization of violence got a little extra juice added to its punch. Often real life or the passage of time can undermine the effectiveness of propaganda: it is possible that Reefer Madness may have been effective when it first came out, but audiences today find its propaganda against drug use obvious, simplistic, risible and, more importantly, ineffective.
From the Dramatica Theory Book