All of us have a shadow part, and it is not something that an "evil" person possesses. The shadow or the dark side of us is what gives us a perspective to the light side and makes us a whole human being.
The patriots who founded this nation had good reasons for adding the Bill of Rights to the Constitution. They wanted to create a society that protects each individual equally and makes everyone accountable.
Reading The Dark Side, as I just have, forces a stomach-turning, jaw-clenching reckoning with Guantanamo, Abu Ghraib, CIA kidnappings, secret prisons, waterboarding, and a shameful list of other soul-shattering abuses.