Some good discussion here, I don't have a great deal to add other than to sum-up/clarify a few points.
The notion that a democracy or democratically-elected republic cannot become tyrannical is exactly the kind of utopianistic naivety which has led to the downfall of personal freedom time and again throughout history. People always think "it could never happen here." If you could go back to around 45 BC and ask a Roman citizen whether they believed their four-and-a-half century old system of government would in one generation be replaced by a single, absolute ruler who could act with near-impunity, do you think he/she would believe you? And, as has already very rightly been pointed out, do you think the citizen masses who put Hitler into power thought he was going to do what he did?
Total paranoia is not the way to live, but the other end of the pendulum--total lack of concern--is equally silly.
I do not think there is a team of techno-thieves watching my computer activity 'round the clock---I still very seldom transmit my CC info via the internet, and never my social security number.
I do not live in a high-crime community---I still lock my doors when I leave the house.
I do not believe my infantile nephew has any suicidal intentions---I still don't leave him alone by a pool.
I have never had to actually perform CPR---I still go back and get retrained every two or three years.
And finally, no I do not believe that every person who seeks government office is an aspiring demigod just waiting for his or her chance to dominate me---I'm still cognizant of the fact that every single one of them is a professional popularity-seeker whose career survival is based on being able to say what people want to hear when they want to hear it. Sounds one holy hell of a lot like a used car salesman, doesn't it? The notion of willingly giving any more control of my life to these people than they already have is just repugnant to me. And yes, whether you or I like it or not, there will always be some people who will abuse their power once they're given it, and no amount of calmly reasoning with them will ever change it. Hence, while I never want to be in a position of having to defend myself, I DO want to make sure that calm reason is not the only thing I can bring to the table if that position is forced on me. Anyone who seeks to limit my options in such a situation is automatically suspect to me, in regards to either their intentions or intelligence.