(I'm gunna respond even though I'm getting downvoted b/c hopefully someone gets something out of this.. but keep it coming! =) )
There is nothing inherently evil in surveillance. In and of itself it's a neutral thing. It's what you do with it that is evil or good.
First I'd say that I don't really see how the NAZIs gain power because of surveillance. Hitler didn't seize power because the SA had some intricate intelligence apparatus. Nor was it the case for the the fascists in Italy, nor Spain. I would argue it was for them simply a tool for the consolidation of power and their fight against subversion.
Just like - in la-la land - if the US government were to turn evil, they would use surveillance to oppress the people. But at that point it's "too-late". The oppression comes first, and then the surveillance to back it up.
"I think it's rather more that the history of states turning fascist..."
I think maybe the larger issues is that the "cyclicality" of history is really more about people seeing patterns where there are none (and historians justifying their jobs). Virtually all the examples we return too are from the beginning of the 20th century. Somehow because of how horrible WW2 was we feel that this may happen again if we aren't careful.
But in reality, history doesn't really "repeat itself" as the old says goes. The NAZI arose during a period of extreme nationalism. There is no reason to believe that this will necessarily happen again. For instance it didn't happen before the end of the 19th century since nationalism is a relatively new concept. And we don't for examples anticipate the return of communism, or disco.
I think at this point in our cultural evolution a return to tyranny is simply impossible. We have so much precedent of the success of democracy and our thinking on human rights has evolved to a point where this is simply unsustainable
to close with some data:
http://thediplomat.com/2013/02/13/5-ways-china-could-become-....
"Statistical analysis shows that authoritarian regimes become progressively more unstable (and democratic transitions more likely) once income rises above $1,000 (PPP) per capita. When per capita income goes above $4,000 (PPP), the likelihood of democratic transitions increases more dramatically. Few authoritarian regimes, unless they rule in oil-producing countries, can survive once per capita income hits more than $6,000 (PPP)."