Root meaning: A principle of fairness which says that everyone should receive only what they deserve. This must be assessed based on an impartial account of how well they have conformed to the law.
Conventional: A principle separate from love which punishes sinners for their crimes, taking vengeance on them. A process of deciding who is the guilty one and taking from him to give back to the innocent.
ACIM: A principle which gives love and forgiveness to everyone with complete impartiality and without limit, which gives no punishment and asks no penalty. This is true fairness because no one has broken God’s laws. Everyone is still the Son of God, still innocent. Thus, the miracle is everyone’s just due (see no order of difficulty in miracles). The world’s justice is really injustice. It is simply a justification for attack, and all attack is unjust. It also makes us believe that God’s Love is separate from His justice, which makes Him seem fearful (see fear of God). See T-25.VIII-IX, M-19.