Yes, a very interesting subject. Fear is the most potent of political weapons. This has been true for centuries. I'm just reading about the English Civil War at the moment. Parlimentarian conspirators used the fear of popery to whip up support against the king. The rebellion in Ulster or St Bart's day massacre were exagerated in scale and de-contextualised to imply the same was capable of occuring in England, with the kings support of course.
I guess it makes sense - fear is a very primative thing and encourages people to seek comfort in a crowd or pack and of course be suspicious of outsiders. Bring 'em together and turn them against a common enemy. The only thing I'd say is you wouldn't have to look at the extreme example of the east german state to see this.