Chapter 1: What Is the Law?

  1. What is the Difference Between Primary Legal Authority and Secondary Legal Authority?
  2. What Are the Key Types of Primary Legal Authorities?
    1. What is a constitution?
    2. What is a statute?
    3. What is a regulation?
    4. What is case law?

The law affects and impacts nearly every aspect of daily life. In the morning, the law ensures that your toothpaste is safe. While driving, the law guides the flow of traffic and design of roadways. On the radio, the law controls the type of advertisements that you hear while listening to the morning news. The law is also involved in the contract you signed when purchasing a cell phone service plan. At work, the law sets standards for how your boss must treat employees. In today’s world there is no area of modern life that is not touched by the law.

But what is “the law”? Generally, the law refers to the entirety of the legal system within a country or state. There are four key types of law (or “primary legal authorities,” which are discussed below): constitutions, statutes, regulations, and judicial decisions. Despite the complexities and sheer size of the law, it has a fixed organizational structure. Familiarity with a few key definitions and concepts will allow anyone to understand the basic structure of the law and the legal system in the United States and begin researching specific areas of the law in greater detail.

This section will distinguish primary legal authority from secondary legal authority and will focus on discussing types and sources of the law. Later sections in this guide will explain how different types of laws function within the United States’ system of federalism and will discuss the three branches of government – the legislative, the executive, and the judiciary – that create, apply, and interpret the law.

Effective legal research usually involves consulting primary legal authority and secondary legal authority. Primary legal authority refers to the documents or sources that are the building blocks of the law. These materials, which include documents like statutes or judicial opinions, are created by legislatures, courts, agencies, or other official bodies. This guide focuses largely on primary legal authorities.

In contrast, secondary legal authority refers to documents or resources that make unofficial comments about the law. Secondary legal authority includes resources like legal dictionaries, legal treatises, and law review articles. These resources helpfully, but unofficially, identify and explain the law. When conducting legal research, a common strategy is to start with a secondary legal authority in order to understand the relevant primary legal authority.

For the most part, primary legal authority is available to the public for free, and later sections of this guide will direct you to resources that will help you identify and obtain primary legal authority. In contrast, high quality secondary legal authorities are often not freely available.

However, a local law library or public law library can provide access to some secondary legal authority, especially if a patron visits in-person.

As mentioned above, there are four key types of primary legal authorities: constitutions, statutes, regulations, and judicial decisions. Together these types of primary legal authorities comprise the law. Each type of primary legal authority has specific and distinct characteristics.

What is a constitution?

A constitution is the fundamental and overarching law of a country or state. Generally a constitution dictates the form of government institutions, grants or limits governmental power, and provides for individual rights and liberties. In the United States there is a federal constitution that applies to the entire country and there are separate state constitutions for each state. See the guide section on HOW POWER IS SHARED IN THE U.S. GOVERNMENT to learn more about the interaction between the federal government and state governments.  

What is a statute?

A statute is an individual law. Distinct from “the law,” which refers to an entire legal system, a statute, sometimes called an “act,” is a law enacted by a legislature. See the guide section on the LEGISLATIVE BRANCH to learn more about legislatures and the lawmaking process.

Statutes can focus on a narrow topic. For example, the Clean Air Act was concerned with protecting air quality from pollutants. Statutes can also cover a wide variety of topics. For instance, the Consolidated Omnibus Budget Reconciliation Act of 1985 addressed subjects as varied as railroads, the postal service, and health insurance coverage. 

What is a regulation?

A regulation is an official rule created by an administrative agency. Regulations and statutes are closely related but distinct: the key difference between them is that statutes are created by the legislature and regulations are created by administrative agencies. Administrative agencies receive their limited rulemaking authority from specific grants of power from the legislature. See the guide section on the EXECUTIVE BRANCH to learn more about agencies and regulations.

What is case law?

Case law is law that is created by the decisions of a court. Generally, case law refers to opinions (statements that explain the court’s decision) written by judges, based on the specific facts of a civil or criminal case. Case law interprets and applies statutes and regulations. See the guide section on the JUDICIAL BRANCH to learn more about judicial decisions, case law, and courts.

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