I just finished reading James Bamford’s The Puzzle Palace: Inside the National Security Agency, America’s Most Secret Intelligence Organization. If you have any interest the intelligence community, spys, or privacy, read this book. It has more information than I ever thought the NSA would possibly let out. (The fact that they did let it out frightens me. What are they hiding?) I can’t emphasize this enough: Read This Book. You’ll be amazed.
At the same time, that capability at any time could be turned around on the American people and no American would have any privacy left, such [is] the capability to monitor everything: telephone conversations, telegrams, it doesn't matter. There would be no place to hide. If this government ever became a tyranny, if a dictator ever took charge in this country, the technological capacity that the intelligence community has given the government could enable it to impose total tyranny, and there would be no way to fight back, because the most careful effort to combine together in resistance to the government, no matter how privately it was done, is within the reach of the government to know. Such is the capability of this technology... I don't want to see this country ever go across the bridge. I know the capacity that is there to make tyranny total in America... That is the abyss from which there is no return. -Senator Frank Church, 1973, referring to the NSA's SIGINT technology