If justice is the most profound responsibility of public life, it is also the one we are least suited to fulfill. It's no mystery why this should be. We're human. Our byways are complicated. The institutions of law are infected with the same shortcomings--greed, dishonesty, weakness, indifference, anger--that give rise to injustice in the first place. On the everyday working level, criminal justice is like chemotherapy. We throw our little poisons at big ones.
This may be the most entertaining irony of human affairs. (Literally entertaining--we get any number of our movies, books and TV shows out of it.) In...