Sources of Criminal Law

Introduction

Although we may not immediately realize it, our daily life is impacted by the nature of our sources of law. In the U.S., our sources of law are public. You are free to find laws online or at a library. This freedom of information is a core tenet of our democracy. You have access to the laws, so you have the power to know your rights and legal obligations. But sometimes laws are confusing and hard to understand. The sources of law also create accountability for the government, such as the checks and balances in the Constitution. Overall, the sources of law shape our society, freedoms, and the criminal justice system as we know it. 

The Common Law

The first source of law is common law. Common law began in Medieval England. It travelled with the English to the American colonies. Eventually, common law principles were “codified” (or written into) the United States Constitution, state constitutions, and statutes—both federal and state. Today’s criminal laws draw from common law and make their own distinctions.

For instance, there is no federal common law. Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938). Although some crimes have common law definitions, federal statutes create their own definition. Federal criminal law relies entirely on statutes (laws passed by Congress) and the Constitution. On the other hand, state law is influenced by common law. In California, the definitions of crimes rely on a mixture of common law and state statutes. 

However, a modern trend is that many states replaced common law definitions when they enacted their own criminal code. Yet states that replaced common law crimes did not necessarily eliminate common law defenses to those crimes. For example, insanity or self defense are common law defenses. Generally, if the state statutes do not expressly provide for the defense, then the defense still relies on common law. To learn more about defenses, you may read Criminal Defenses.

The Constitution

Following common law, the United States Constitution is one of our earliest sources of law. The Constitution defines just three crimes: treason, piracy, and counterfeiting.  While the Constitution does not create many criminal laws, it does create a lot of criminal procedure. 

Criminal procedure protects the rights of the criminally accused. For instance, the 5th through 8th Amendments provide the criminally accused with the right to an attorney, to remain silent, and more. The Constitution also grants Congress the power to pass more laws. Congress accordingly passes criminal laws (which will be explored later in this article). To learn more about the difference between criminal law and criminal procedure, visit this link. 

Modern Penal Code (MPC)

There is also a Model Penal Code (MPC) drafted by the American Law Institute. The MPC synthesizes common law, constitutional law, and statutes (written law) in order to provide a framework for modern law. This comprehensive framework is not explicitly federal or state law, but merely a guide for both.  

Federal and State Code 

Drawing from the MPC framework, let’s consider what the federal and state laws are. At both the federal and state level, the legislature passes laws that are called statutes. Statutes are also known as codes—these terms are interchangeable.

At the federal level, Congress passes laws that are organized under United States Code (U.S.C. or U.S. Code). The U.S. Code is not limited to criminal law—it covers a range of federal laws. The most common crimes can be found in Title 18 of the U.S. Code, but crimes are also listed throughout the code including drug crimes in Title 21 of the U.S. Code and immigration crimes in Title 8 of the U.S. Code. 

At the state level, the state legislature passes laws that become state code. In California, criminal law is passed into the California Penal Code (Cal. P.C.). A good way to understand how criminal law is applied in federal and state court is to look at the model jury instructions. Jury instructions outline the elements of each crime, and explain what principles and laws are applicable to the crime. The elements are important because each one must be proven beyond a reasonable doubt by the prosecutor.

Courts and Case Law

Courts are also sources of law because their rulings produce case law. When judges make a ruling, their ruling forms a precedent for other judges to follow. Within the ruling, a judge also discusses their interpretation of the laws that apply to the case, and how that interpretation led them to their decision. Altogether, this process creates case law. U.S. Supreme Court case law can be found here; other resources for case law are here.

Administrative Law

Administrative agencies also have the power to create sources of law because they enact rules and regulations. Some violations of those rules and regulations are considered criminal. Therefore, some rules and regulations are sources of criminal law. For instance, consider how the Environmental Protection Agency (EPA) regulates environmental crimes. Regulations created by the EPA are annually codified in the U.S. Code of Federal Regulations (CFR) under Title 40: Protection of Environment. In some cases, a breach of the CFR results in criminal penalties.

Conclusion

In sum, the sources of law, and their public nature, are a key element of our democracy and criminal justice system.