Precedent is the principle in law of using the past in order to assist in current interpretation and decision-making. Precedent can be of two types. Binding or mandatory precedent is a precedent under the doctrine of stare decisis that a court must consider when deciding a case. Advisory precedent are cases which a court may use but is not required to use to decide its cases. In general, binding precedent involves decisions made by a higher court in a common law jurisdiction.
Precedent in law can also be divided into custom and case law.
Long-held custom which has traditionally been recognized by courts and judges is the first kind of precedent. Custom can be so deeply entrenched in the society at large that it gains the force of law. There need never have been a specific case decided on the same or similar issues in order for a court to take notice of customary or traditional precedent in its deliberations.
The other type of precedent is case law. This type of precedent is granted more or less weight in the deliberations of a court according to a number of factors. Most important is whether the precedent is “on point,” that is, does it deal with a circumstance identical or very similar to the circumstance in the instant case? Second, when and where was the precedent decided? A recent decision in the same jurisdiction as the instant case will be given great weight. Next in descending order would be recent precedent in jurisdictions whose law is the same as local law. Least weight would be given to precedent which stems from dissimilar circumstances, older cases which have since been contradicted, or cases in jurisdictions which have dissimilar law.
Precedents viewed against passing time can serve to establish trends, thus indicating the next logical step in evolving interpetations of the law. For instance, if women have been enjoying greater and greater equality under the law, then the next legal decision on that subject may serve to bring still greater equality.
When a precedent becomes of significant importance to an issue, or represents new or changed law in a particular issue, that precedent is often referred to as a Landmark case or landmark decision.
Stare decisis is a Latin term (“to stand by things decided”) used in common law to express the notion that prior court decisions must be recognized as precedents, according to case law. This doctrine is not held within most civil law jurisdictions as it is argued that this prinicple interferes with the right of judges to interpret law and the right of the legislature to make law. Most such systems, however, recognize the concept of jurisprudence constante, which argues that even though judges are independent, they should rule in a predictable and non-chaotic manner.
The principle of stare decisis can be divided into two components. The first is the rule that a decision made by a higher court is binding precedent which a lower court cannot overturn. The second is the principle that a court should not overturn its own precedents unless there is a strong reason to do so and should be guided by principles from lateral and lower courts. The second principle is an advisory one which courts can and do occasionally ignore.
In general, a common law court system has trial courts, intermediate appellate courts and a supreme court. The lower courts administer most day-to-day justice. The lower courts are bound to follow precedents established by the appellate court for their region and the supreme court. Appellate courts are only bound to follow supreme court decisions. The application of the doctrine of stare decisis from a higher court to a lower court is sometimes called vertical stare decisis.
A supreme court is not bound by any lower precedent and, today in most jurisdictions, a court of last resort may overturn its own precedents if warranted; see the Practice Statement made by the House of Lords, a well known example of such principle in Commonwealth countries. Stare decisis nonetheless operates in a supreme court as a discretionary principle by which the court will not overturn its own precedents in the absence of a strong reason to do so, in order to foster predictability of the law.
In the United States federal court system, the intermediate appellate courts are divided into “circuits”. Each panel of judges on the court of appeals for a circuit is bound to follow the prior appellate decisions of the same circuit. Precedents of a United States court of appeals may be overruled only by the court en banc, that is, a session of all the active appellate judges of the circuit, or by the United States Supreme Court. When a court binds itself, this application of the doctrine of precedent is sometimes called horizontal stare decisis. The State of New York has a similar appellate structure as it is divided into four appellate departments supervised by the final New York State Court of Appeals. Decisions of one appellate department are not binding upon another, and in some cases the departments differ considerably on basic points of law.
And while lower courts are bound in theory by higher court precedent, in practice judges may sometimes attempt to evade precedents, by distinguishing them on spurious grounds. The appeal of a decision that does not follow precedent may also not occur as the expense of an appeal may prevent the losing party from doing so and thus the lower court decision may stand even though it does not follow the higher court decision as the only way a decision can enter the appeal process is by application of one of the parties bound by it.
Occasionally, the application of prior case law results in court decisions which the judge explicitly states personal disagreement with the judgment he or she has rendered, but that he or she is required to do so by binding precedent, that is, the issue at had was already decided by a higher court. Note that binding precedent is thus distinct from stare decisis, which are decisions from lateral courts, lower courts, or the same court, and affords deviation based upon “compelling justification”. (see Hilton v. S. Carolina Pub. Rys. Cmsn., 502 U.S. 197, 202, 112 S. Ct. 560, 565 (1991).)
In the United States, stare decisis can interact in non-intuitive ways with the federal and state court systems. On an issue of federal law, a state court is not bound by an interpretation of federal law at the district or circuit level, but is bound by an interpretation by the United States Supreme Court. On an interpretation of state law, whether common law or statutory law, the federal courts are bound by the interpretation of a state court of last resort, and are normally required defer to the precedents of intermediate state courts as well.
Courts may choose to follow precedents of other jurisdictions, but this is not an application of the doctrine of stare decisis, because foreign decisions are not binding. Rather, a foreign decision that is followed on the basis of the soundness of its reasoning will be called persuasive authority–indicating that its effect is limited to the persuasiveness of the reasons it provides.
Stare decisis is not usually a doctrine used in civil law court system, because it violates the principle that only the legislature may make law. In theory therefore, lower courts are generally not bound to precedents established by higher courts. In practice, the need to have predictability means that lower courts generally defer to precedents by higher courts and in a sense, the highest courts in civil law jurisdictions, such as the Cour de cassation and the Conseil d’État in France are recognized as being bodies of a quasi-legislative nature.
The doctrine of stare decisis also influences how court decisions are structured. In general, court decisions in common law jurisdictions are extremely wordy and go into great detail as to the how the decision was reached. This occurs to justify a court decision on the basis of previous case law as well as to make it easier to use the decision as a precedent in future cases. By contrast, court decisions in civil law jurisdictions tend to be extremely brief, mentioning only the relevant legislation and not going into great detail about how a decision was reached. This is the result of the civil law view that the court is only interpreting the view of the legislature and that detailed exposition is unnecessary. Because of this, much more of the exposition of the law in civil law nations is done by academic jurists which provide the explanations that in common law nations would be provided by the judges themselves.
There is much discussion about the virtue and irrationality of using case law under such a system. Supporters of the system argue that it makes decisions predictable, that is, a business person can be assured of the same decision in the same sort of case. The argument most often used against the system is that it is undemocratic as it allows unelected judges to make law.