All backed up by coercion. But hey!...we get the government we elect (sometimes).

The "First Circle" by Aleksandr Solzhenitsyn is an instructive thing to read. It concerns scientists imprisoned in a "sharashka" where they are working to analyze a phone recording to identify the person speaking. They start out with over a thousand possible voice candidates and, through the progress of the story, gradually reduce the number of candidates, until finally they have to report they can narrow it down to a dozen, but that is the end of the road. The security commandant basically says, "That's good enough. We will simply imprison the lot of them." So, the imposition of tyranny really does not depend on accurate surveillance at all, but on the exercise of naked, unlimited, arbitrary power.