Third, punishment reduces crime by deterring would-be criminals. Someone who is tempted to commit a crime might not do so if he knows he might be punished. Obviously, the threat of punishment is not always effective; sometimes people break the law anyway. But there will be less misconduct if punishments are threatened. Imagine what would happen if the police stopped arresting thieves: surely there would be a lot more theft. Deterring crime thus prevents unhappiness.