Criminal law's audience is law enforcers, not ordinary citizens. For the most part, criminal law regulates actors in the legal system, while popular norms--morals--regulate the conduct of the citizenry. In a legal system structured as ours is, criminalization can work against the very norms on which it rests, meaning that popular norms may tend to move in the opposite direction from the law. Of course, most crimes are not self-defeating. But self-defeating crimes may be more common than one might suppose. And the more common self-defeating crimes are, the harder it is to know what it means to say that criminal law ought to follow popular norms. Sometimes, the best way for the legal system to advance or reinforce norms may be to ignore them.
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