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Law 792-GRD: Legal Research and Writing for LLMs: Unit 2: Courts


This page will provide you with an overview of how American courts are structured and how the concept of 'authority' works with regard to legal information.

At the end of this lesson you should be able to:

  • Understand the basic structure of state and federal courts
  • Articulate the difference between a mandatory and persuasive law
  • Explain how to determine the value of an individual case or citation


That which can bind or influence a court. This includes case law, legislation, constitutions, administrative regulations, and writings about the law. Authority can be mandatory or persuasive.

  • Mandatory Authority- Authority that a given court is bound to follow. Mandatory authority is found in constitutional provisions, legislation, and court cases. Compare with persuasive authority.
  • Persuasive  Authority- That law or reasoning which a given court may, but is not bound to, follow. For example, decisions from one jurisdiction may be persuasive authority in the courts of another jurisdiction. Compare with mandatory authority.

Court Opinion
The written expression of the reasons why a decision was reached in a case.

The power given to a court by a constitution or a legislative body to make legally binding decisions over certain persons or property, or the geographical area in which a court's decisions or legislative enactments are binding.

Stare Decisis (Precedent)
The legal doctrine that states when a court has formulated a principle of law as applicable to a given set of facts, it will follow that principle and apply it in future cases where the facts are substantially the same. It connotes the decision of present cases on the basis of past precedent.

Supreme Court
(1) The court of last resort in the federal judicial system (the supreme court of the united states also has original jurisdiction in some cases); (2) in state judicial systems, except New York and Massachusetts, the highest appellate court or court of last resort.

Intermediate Appellate Court
A court having jurisdiction to review decisions of a trial-level or other lower court. Not all jurisdictions have an intermediate appellate level.

Thinking Outside the Box(es)

Think about your family tree. Do you find where someone "sits" on the tree influences how you value their opinion? Are your parents' rules authoritative in your own home? How would those same rules be seen by your cousins?

It can be helpful to think of courts and their authority in this same manner. The direct line above a jurisdiction is its mandatory authority. All other authorities will be persuasive. Even this persuasive value can vary depending on the relationship. The further from one's own branch the less value it may be perceived to have, in the same way you might value your peer (who is on your level) more than your baby sister (who may not have tackled the world yet in the same manner as you.)

image of family tree with Supreme Court at trunk representing parents, the appellate courts as branches, and trial courts as leaves



Additional Resources

Legal Research in a Nutshell, Ch. 3, pp.53-58

YouTube Videos:

Understanding Courts & their Authority

America is a common law system, which means courts decide disputes and in so doing develop legal principles that apply to future similar cases. The prior decided cases create what we call precedent. Common law precedent operates within the jurisdiction from which it was issued as mandatory authority. Other jurisdictions may look at these decisions persuasively, but are not bound to the decisions outside their jurisdiction.

Since courts are bound to the precedent of their jurisdiction when settling legal disputes, it is important for legal researchers to understand the basic structure of the court system and the hierarchy of their authority.

Determining whether a given case is binding is a necessary skill for any legal researcher. It can be tricky and it may take a bit of time and practice to hone that skill. Use the slides below to test yourself and see how well you can apply the concept. If you are still struggling, ask for help!


What court am I in?:

It is important to understand the relationship between federal and state court systems. In the U.S. the Constitution reserves certain powers for the federal government. All other governmental functions are left to state control. Within the state and federal systems there are further geographic subdivisions, as well as hierarchical layers. All of this relates to a much more complex aspect of law called jurisdiction.

You will study jurisdiction in excruciating detail in Civil Procedure. For now it is simply enough to remember the importance of understanding within which system (state or federal) and which subpart (for example, the 2nd District of Illinois) your research problem takes place. You will also need to understand the basic hierarchy within each system for the purpose of evaluating the authority of a given resource.

Jurisdiction Maps

Below are maps showing the geographic areas covered by Federal and Illinois appellate courts. Click on the image to open the court website for more information.

Federal Circuit Courts of Appeal

Map showing the 11 Numbered Federal Circuit Courts of Appeal and their included district courts

Illinois District Courts of Appeal

Map of the 5 Illinois Circuit Courts of Appeal

Mandatory or Persuasive? Test yourself with these slides