Sources of Criminal Law in the US

Criminal law in the United States is a multifaceted legal framework that defines criminal offences, outlines the procedures for arrest and trial, and prescribes punishments for offenders. It is derived from several key sources, each playing a vital role in shaping how criminal behaviour is regulated. These sources include common law, constitutions, statutes and ordinances, administrative rules, appellate court decisions, and international law. Understanding these origins is essential to grasping the complexities of the US legal system.

1. Common Law
Common law, often referred to as judge-made law, has deep historical roots. Originating in England during the twelfth century, it was established when judges began ruling that specific actions constituted crimes. Early decisions by English judges defined offences like murder, arson, burglary, and rape as crimes against the state. Over time, these judicial rulings formed a body of unwritten laws and customs, which later became the foundation of the legal system in the American colonies.

A key feature of common law is the principle of precedent. When a court makes a ruling, it sets a precedent that must be followed by other courts in similar cases. This concept, known as stare decisis meaning "to let the decision stand", helps ensure consistency and fairness in the judicial process. For example, if a court rules on a murder case, future courts must adhere to that ruling when faced with similar facts.

2. Constitutions
The US Constitution, along with state constitutions, plays a critical role in shaping criminal law. Article VI of the U.S. Constitution declares that it is "the supreme Law of the Land", and that all judges in every state are bound by it. If any law conflicts with the Constitution, it can be struck down by the US Supreme Court. This principle of judicial review ensures that no law violates the fundamental rights and principles outlined in the Constitution.

Similarly, each state has its own constitution, which governs state-specific laws. For instance, while the US Constitution guarantees the right to a fair trial, state constitutions may provide additional procedural safeguards or define specific crimes in greater detail. All local laws must align with both the US and state constitutions, emphasising the hierarchy of legal authority.

3. Statutes and Ordinances
A large portion of criminal law in the US comes from statutes and ordinances, which are laws passed by legislative bodies. Congress enacts federal statutes, while state legislatures create laws for individual states. City councils also pass ordinances that regulate local criminal behaviour. These legislative efforts define many common crimes, including homicide, rape, robbery, and burglary, and are codified in criminal codes at both the federal and state levels.

For example, statutory laws define the penalties for robbery at both the federal and state levels, ensuring that criminal conduct is clearly defined and consistently punished. There is often overlap between state and federal statutes, particularly in areas such as drug enforcement. In cases where local law enforcement struggles to control certain types of crime, federal statutes may supplement state laws to provide additional tools for prosecution.

4. Administrative Rules with Criminal Penalties
Governmental agencies also contribute to criminal law through the creation of administrative rules that carry criminal penalties. Agencies like the Federal Trade Commission (FTC), the Internal Revenue Service (IRS), and the Environmental Protection Agency (EPA) have the authority to create rules that function like laws. These agencies investigate violations, enforce regulations, and impose sanctions on those who break the rules.

For instance, the IRS has the power to enforce tax laws and prosecute individuals for income tax evasion. The EPA, on the other hand, can investigate companies for illegal dumping of hazardous waste, a crime that endangers public health and the environment. These administrative rules add another layer of regulation to ensure compliance with federal and state laws.

5. Appellate Court Decisions
Appellate court decisions, especially those from the US Supreme Court, serve as a significant source of criminal law through the development of case law. These rulings often result from the interpretation of existing statutes or the establishment of legal principles in areas where laws are unclear or not yet codified. When appellate courts interpret laws, their decisions become binding, effectively creating new legal standards.

An example of this is the famous Miranda v Arizona decision, where the US Supreme Court ruled that suspects must be informed of their rights upon arrest, including the right to remain silent. This decision established a vital procedural safeguard in criminal cases and has since influenced how law enforcement agencies handle arrests and interrogations across the country.

6. International Law
International law is an increasingly important source of US criminal law, particularly in areas such as human rights, war crimes, and terrorism. While US law traditionally focuses on domestic concerns, the influence of treaties, conventions, and international agreements has grown over time. International law enters the US legal system primarily through treaties ratified by the Senate, which become binding domestic law under the US Constitution.

For instance, the US is a signatory to international treaties like the Geneva Conventions, which set rules for the treatment of prisoners of war and civilians in conflict zones. These conventions influence US military law and criminal prosecutions for war crimes. Additionally, international conventions against terrorism, drug trafficking, and human trafficking have shaped US laws and enforcement practices.

The International Criminal Court, although not formally recognised by the US as having jurisdiction over its citizens, indirectly influences US law by setting international norms regarding crimes such as genocide and crimes against humanity. The US often aligns its domestic legal standards with these norms, especially in areas of global concern like terrorism.

In conclusion, the sources of criminal law in the US are diverse and interrelated, providing a comprehensive framework for addressing criminal behaviour. Common law traditions, constitutional mandates, statutes, administrative rules, appellate court decisions and international law all play a crucial role in shaping the legal landscape. Together, they ensure that criminal law is consistent, fair, and adaptable to the evolving needs of society.