The ability of so many people to live comfortably with the idea of capital punishment is perhaps a clue to how so many Europeans were able to live with the idea of the Holocaust: Once you accept the notion that the state has the right to kill someone and the right to define what is a capital crime, aren't you halfway there?
Roger Ebert (2009). “Roger Ebert's Four Star Reviews--1967-2007”, p.516, Andrews McMeel Publishing