The Judicial Branch (the court system) creates law in the form of judicial opinions,
which are published as case law.
Case Law Research
Structure of the Judicial System
In order to research case law, it is important to understand the structure of the judicial system. Anytime that we are looking at case law, we must first identify the jurisdiction and/or level of authority within which that ruling applies.
The U.S. court system fundamentally has three levels: the trial courts; the appellate courts which review and may overturn judicial actions in trial court cases; and the supreme court or "court of last resort" whose actions are binding on lower courts. On a federal level, these courts are called the District Courts, Circuit Courts and Supreme Court. Within individual states, the specific names of these courts may vary (ex - in Maryland, the "Appellate Court" is the court of last resort).
District Courts
Every state has 1-4 District Courts (federal trial courts), which are organized geographically.
District Courts do not generally make law. Judicial opinions or rulings at the trial court level, are only binding on the specific parties involved. They may be persuasive to other courts (meaning that they may be used as a legal argument / convince another court to act similarly), but have no authority.
Circuit Courts
The various district courts are organized into 13 Circuits (appellate courts). These include the 1st through 11th Circuits, the DC Circuit, as well as the Federal Circuit. 12 of the circuits are based on geography; the Federal Circuit is the only court set aside for specific subject matter (issues such as intellectual property, government contracts, etc.).
It is important to note that Circuit Courts, as courts of appeals, uphold or overturn the judicial actions in the previous (trial court) case. They do not examine the verdict itself.
Opinions issued by a Circuit Court are binding within that particular circuit. For example, if a 10th Circuit judge issues an opinion, that opinion is binding on every district court within the circuit as well as any future rulings made by the 10th Circuit. Outside of the relevant circuit, these opinions are only persuasive.
Sometimes different circuit courts may issue differing rulings on the same issue. When this occurs, it is called a circuit split. This is one of the most common ways that the Supreme Court gets involved on a particular issue -- it creates a problem of people experiencing a different version of the law depending on where they live.
Supreme Court
An opinion issued by the United States Supreme Court is binding over the entire United States.
Primary Sources for Case Law
In legal research, primary sources consist of "the official pronouncements of the governmental lawmakers."
Primary sources from the Judicial Branch are not published or found as reliably as those from other branches of the government. There is only one "official" publication containing federal case law: U.S. Reports, which publishes judicial opinions of the Supreme Court.
Cases are generally cited as follows:
Case, Reporter vol. name pg. (jurisdiction, court, date).
So, Price v. Garland, 45 F.4th 1059 (D.C. Cir. 2022) references the case Price vs. Garland, which was published in volume 45 of the Federal Reporter, 4th series, beginning on page 1059, and which took place in the D.C. Circuit Court in 2022.
Formats in which you can find case law include:
'Slip' Opinions. These are the first version of an opinion. Some slip opinions become reported opinions; others do not. Unreported opinions are not considered legally binding, and some jurisdictions do not allow them to be used in legal arguments.
Slip opinions are published by the court/judge (and, more recently, by govinfo.gov). You can also find Supreme Court slip opinions in HeinOnline.
- U.S. Supreme Court Library This link opens in a new window
Unreported opinions can be found in research tools such as WestLaw or LexisNexis. These opinions can often be distinguished by their alternative citations ex. 2022 WL 5240551 (however, this same format is used for reported cases that have not yet been assigned a formal citation).
- Westlaw Campus Research This link opens in a new window
Reported Opinions. Case law which is "reported" or formally published, is published in reporters.
U.S. Reports is the only official government reporter for case law, and it publishes decisions of the Supreme Court. U.S. Reports is generally published on a delayed basis; for example, as of December 2022, the most recent volume available is the one ending in June 2015.
Access U.S. Reports via...
- U.S. Supreme Court Library This link opens in a new window
The Federal Reporter is a commercial publication which reports Circuit Court cases.
Access the Federal Reporter via...
- Westlaw Campus Research This link opens in a new window
Other sources for Circuit Court opinions:
The Federal Supplement is a commercial publication which reports District Court cases.
Access the Federal Supplement via...
- Westlaw Campus Research This link opens in a new window
Other sources for Circuit Court opinions:
"Official" case law reporters do not account for currency or for subject in their organization; they are strictly chronological.
There are also other commercially-published reporters, some of which have additional features as well as organization by currency or subject (for example, Supreme Court Reporter).
Case Documents
For the purposes of legal research, we focus mostly on the judicial opinions, as these are what ultimately formulate case law. However, there are many other kinds of documents (filings) which are produced in the course of a case. Usually, these filings are listed in a complete history in the form of a docket.
While these additional documents have no legal force, they can shed light on the final ruling, the particular arguments used, and other aspects of the case.
Types of case documents that you may find in a docket include:
- Complaint
- Answer
- Motion for Judgment
- Brief (legal arguments)
U.S. Supreme Court. Case documents for U.S. Supreme Court cases are typically made available through the Supreme Court website:
There are several additional case documents that are unique to Supreme Court cases:
- Petition for a writ of certiorari. Every U.S. Supreme Court case docket begins with this document, which is the petition for a case to be heard before the Supreme Court;
- Brief of respondents in opposition [to the writ of certiorari, saying that the Supreme Court should not hear the case);
- Amicus curiae brief. Briefs generally make up the legal argument of a particular case. Amicus curiae briefs are filed by parties who are not directly involved in a case before the Supreme Court, but who feel that they have some investment and/or something to add to the case argument. The Supreme Court may choose to consider or to ignore these briefs.
Other Federal Courts. Other federal case documents are sometimes made available through individual jurisdictions' websites, but are generally through the PACER system:
NOTE: PACER is currently a fee-based system, with small charges for each document accessed (but these can add up!). While it is rare for PACER to bill a user who is pulling less than $30 worth of documents in a given quarter, it is important to take note of the possible fees. As of December 2022, there is legislation in progress (but not yet passed) to eliminate fees for PACER.
PACER is the central repository for all federal court filings. For many cases, PACER contains a full docket sheet listing every document filed in the course of a case. For more-recent cases, it is also generally possible to obtain PDF copies of the documents themselves. However, it is important to note that some cases on a docket sheet will not have a corresponding document. If an item listed on the docket sheet has no document number or link, it indicates that that item is a minute order -- there is no document or information beyond what is included on the docket sheet.
It is important to note that PACER is the root source for federal court filings. Other sources which sometimes contain case documents, such as WestLaw, generally pull from PACER. Therefore, if a document is not in PACER, it generally does not exist!
Citators ("Shepardizing")
Citators are legal research tools which help you identify whether a case is still "good law" -- that is, whether it still holds authority, has been challenged, or has been overturned. Citators also trace the history of a case through the levels of the judicial system, and help you to identify related cases -- whether past cases used to support a case's argument, or later cases which use a particular case as a basis.
WestLaw's citator tool is called KeyCite. You may also see the term "Shepardizing" to refer to the process of using a citator. Shepard's is LexisNexis' citator tool, and was the first one on the market, so it's name is sometimes used as a shorthand for checking the status of case law, regardless of the tool you use.
KeyCite uses a flag system to identify the status of a particular case:
A red flag indicates that a case, or at least some crucial point of law in the case, is no longer "good law." A yellow flag indicates that a particular case has negative history -- generally meaning that various other cases have debated the nuances of this case, but the case is still "good law." A yellow flag may warrant further research to determine which particular nuances/points of the case have been debated (to see how this may affect your use of the case). A blue-and-white striped flag simply means that the case is currently being appealed.
A KeyCite flag is only the first step in understanding the history of a case
Negative Treatment
The Negative Treatment tab will show you precisely which case(s) resulted in the red or yellow flag -- which case(s) overturned or distinguished (disagreed with nuances of) the case.
For each case listed, this page will also tell you:
- Which had the greatest negative treatment of / impact on the authority of this case (if there is more than one case involved);
- The extent to which a case deals with the particular case you are investigating;
- The Headnotes in the case you are investigating which are referenced in these other cases (see the Headnotes tab for more information).
History
The History tab will show you the progression of a particular case through the court system, with KeyCite information for each.
Citing References
The Citing References tab will show you cases and other documents which cite to the case you are investigating. Similarly to the Negative Treatment tab, it will tell you how each of these citing cases is using your particular case (does it merely examine your case? distinguish it i.e., pull out nuances? overturn it?); the depth to which it address your particular case; and the relevant headnotes.
Note that the Citing References include not only case law, but also secondary sources, administrative decisions, and other kinds of legal documents.
Headnotes & the Key Number System
Headnotes are a way of organizing (and facilitating searching of) case law based on subject. They are generally only found in subscription legal research tools like WestLaw. Each case in WestLaw is assigned a series of headnotes. Attorney editors manually review each case / judicial opinion and mark up the key legal concepts addressed by that particular case.
Note that headnotes are distinct from the holdings of a judicial opinion, which are the answers to the specific questions posed by that case. Headnotes, on the other hand, identify all of the legal concepts at issue or addressed in that case.
Headnotes can help you to identify the main legal concepts at issue in a particular case; determine which other cases use your initial case as a basis with regards to a specific legal concept; and identify cases in general which deal with a specific legal concept.
Key Numbers hierarchically organize legal concepts. Each specific legal concept has a Key Number assigned, and like-concepts are organized together. Like Headnotes, Key Numbers are specific to subscription legal research tools.
(Note - Key Number is the system used by WestLaw specifically, but other legal databases have their own versions).
In WestLaw, Headnotes are typically linked to a specific Key Number.
Ex - In the example above, Headnote #4 is connected to a Key Number labeled "Motion pictures and videos." Clicking on the Key Number will show that this number is 92K1892, that it is located in the area of Entertainment, specifically as it pertains to Freedom of Speech, Expression, and Press, and that this legal concept is categorized under Constitutional Law.
Thus, we know that the above Headnote (and the case it is from) deals with the issue of motion pictures specifically as they pertain to the Constitutional right of freedom of speech -- among other topics of course!
In addition to starting from a case and viewing the associated Headnotes/Key Numbers, you can also go directly into the Key Number system and browse to look for cases pertaining to a specific legal concept.
