"When people in authority want the rest of us to behave, it matters--first and foremost--how they behave. This is called the "principle of legitimacy," and legitimacy is based on three things. First of all, the people who are asked to obey authority have to feel like they have a voice--that if they speak up, they will be heard. Second, the law has to be predictable. There has to be a reasonable expectation that the rules tomorrow are going to be roughly the same as the rules today. And third, the authority has to be fair. It can't treat one group differently from another. All good parents understand these three principles implicitly. If you want to stop little Johnnie from hitting his sister, you can't look away one time and scream at him another. You can't treat his sister differently when she hits him. And if he says he really didn't hit his sister, you have to give him a chance to explain himself. How you punish is as important as the act of punishing itself."