Which of the following is NOT considered a source of criminal law?

Social norms are informal understandings or expectations that govern the behavior of individuals within a society. They are not codified laws and do not carry legal penalties for their violation in the same way that laws do. While social norms can influence behavior and might inform the creation of laws, they do not constitute a direct source of criminal law.

In contrast, federal constitutions, state statutes, and judicial decisions are formal sources of law. Federal constitutions establish the framework for government and fundamental rights, state statutes are laws enacted by the state legislatures, and judicial decisions refer to the interpretations of laws as made by the courts, establishing legal precedents. Each of these plays a crucial role in shaping and defining what constitutes criminal conduct under the law. Thus, social norms lack the formal legal authority necessary to be recognized as a source of criminal law.