An interesting, philosophical discussion of silencing as a technique, particularly in political discourse.  This paragraph gives a good example:

Silencing is by no means limited to its target. The Fox channel engages in silencing when it describes itself as “fair and balanced” to an audience that is perfectly aware that it is neither. The effect is to suggest that there is no such thing as fair and balanced — that there is no possibility of balanced news, only propaganda. The result is the silencing of every news organ, by suggesting a generalized gross insincerity.

That last sentence is a pretty scary point, that I hadn't quite fully understood till now.