Stare decisis (from the Latin phrase Stare decisis et non quieta movere, "Maintain what has been decided and do not alter that which has been established") is the legal principle by which judges are obliged to obey the precedents established by prior decisions.
Stare decisis is the policy of the court to stand by precedent; the term is but an abbreviation of stare decisis et quieta non movere — "to stand by and adhere to decisions and not disturb what is settled." Consider the word "decisis." The word means, literally and legally, the decision. Nor is the doctrine stare dictis; it is not "to stand by or keep to what was said." Nor is the doctrine stare rationibus decidendi — "to keep to the rationes decidendi of past cases." Rather, under the doctrine of stare decisis a case is important only for what it decides — for the "what," not for the "why," and not for the "how." Insofar as precedent is concerned, stare decisis is important only for the decision, for the detailed legal consequence following a detailed set of facts.
In other words, stare decisis applies to the holding of a case, rather than to obiter dicta. As the United States Supreme Court has put it: "dicta may be followed if sufficiently persuasive but are not binding."
The doctrine that holdings have binding precedential value is not valid within most civil law jurisdictions as it is argued that this principle 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 judge in a predictable and non-chaotic manner. Therefore, judges' right to interpret law does not preclude the adoption of a small number of selected binding case laws.
The principle of stare decisis can be divided into two components. The first is the rule that a decision made by a superior court is binding precedent (also known as mandatory authority) which an inferior court cannot change. 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 inferior courts. The second principle, regarding persuasive precedent, is an advisory one which courts can and do ignore occasionally.
Generally, a common law court system has trial courts, intermediate appellate courts and a supreme court. The inferior courts conduct almost all trial proceedings. The inferior courts are bound to obey precedents established by the appellate court for their jurisdiction, and all supreme court precedent.
The Supreme Court of California's explanation of this principle is that
[u]nder the doctrine of stare decisis, all tribunals exercising inferior jurisdiction are required to follow decisions of courts exercising superior jurisdiction. Otherwise, the doctrine of stare decisis makes no sense. The decisions of this court are binding upon and must be followed by all the state courts of California. Decisions of every division of the District Courts of Appeal are binding upon all the justice and municipal courts and upon all the superior courts of this state, and this is so whether or not the superior court is acting as a trial or appellate court. Courts exercising inferior jurisdiction must accept the law declared by courts of superior jurisdiction. It is not their function to attempt to overrule decisions of a higher court.
Appellate courts are only bound to obey supreme court decisions. The application of the doctrine of stare decisis from a superior court to an inferior court is sometimes called vertical stare decisis.
However, in Federal systems the division between Federal and local law may result in complex interactions. For example, state courts in the United States are not considered inferior to Federal courts but rather constitute a parallel court system. While state courts must defer to federal courts on issues within federal jurisidiction such as constitutional issues, federal courts must defer to state courts on issues of state law.
The idea that a judge is bound by (or at least should respect) decisions of earlier judges of similar or coordinate level is called horizontal stare decisis.
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 obey 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 interpretations of law.
The British House of Lords was not strictly bound to always follow its own decisions until the case London Street Tramways v London County Council  AC 375. After this case, once the House had given a ruling on a point of law, the matter was closed unless and until Parliament made a change by statute. This is the most strict form of the doctrine of stare decisis. (One not applied, previously, in common law jurisdictions, where there was somewhat greater flexibility for a court of last resort to review its own precedents.)
This situation changed, however, after the issuance of the Practice Statement of 1966. It enabled the House of Lords to adapt English law to meet changing social conditions. In R v G & R 2003, the House of Lords overruled its decision in Caldwell 1981, which had allowed the House to establish mens rea ("guilty mind") by measuring a defendant's conduct against that of a "reasonable person," regardless of the defendant's actual state of mind.
However, the Practice Statement has been seldom applied by the House of Lords, usually only as a last resort. As of 2005, the House of Lords has rejected its past decisions no more than 20 times. They are reluctant to use it because they fear to introduce uncertainty into the law. In particular, the Practice Statement stated that the Lords would be especially reluctant to overrule themselves in criminal cases because of the importance of certainty of that law. The first case involving criminal law to be overruled with the Practice Statement was Anderton v Ryan (1985), which was overruled by R v Shivpuri (1986), two decades after the Practice Statement. Remarkably, the precedent overruled had been made only a year before, but it had been criticised by several academic lawyers. As a result, Lord Bridge stated he was "undeterred by the consideration that the decision in Anderton v Ryan was so recent. The Practice Statement is an effective abandonment of our pretention to infallibility. If a serious error embodied in a decision of this House has distorted the law, the sooner it is corrected the better." Still, the House of Lords has remained reluctant to overrule itself in some cases; in R v Kansal (2002), the majority of House members adopted the opinion that R v Lambert had been wrongly decided, but declined to depart from their earlier decision.
In the United States Supreme Court, the principle of stare decisis is most flexible in constitutional cases:
For example, in the years 1946–1992, the U.S. Supreme Court reversed itself in about 130 cases. The U.S. Supreme Court has further explained as follows:
The doctrine of binding precedent or stare decisis is basic to the English legal system, and to the legal systems that derived from it such as those of Australia, Canada, Hong Kong, Pakistan, Singapore and New Zealand. A precedent is a statement made of the law by a Judge in deciding a case. The doctrine states that within the hierarchy of the English courts a decision by a superior court will be binding on inferior courts. This means that when judges try cases they must check to see if similar cases have been tried by a court previously. If there was a precedent set by an equal or superior court, then a judge should obey that precedent. If there is a precedent set by an inferior court, a judge does not have to follow it, but may consider it. The House of Lords (now the Supreme Court) however does not have to obey its own precedents.
Only the statements of law are binding. This is known as the reason for the decision or ratio decidendi. All other reasons are "by the way" or obiter dictum. See Rondel v. Worsley  1 AC 191. A precedent does not bind a court if it finds there was a lack of care in the original “Per Incuriam”. For example, if a statutory provision or precedent had not been brought to the previous court's attention before its decision, the precedent would not be binding. Also, if a court finds a material difference between cases then it can choose not to be bound by the precedent. Persuasive precedents are those that have been set by courts lower in the hierarchy. They may be persuasive, but are not binding. Most importantly, precedents can be overruled by a subsequent decision by a superior court or by an Act of Parliament.
Judges in the UK use three primary rules for interpreting the law. The normal aids that a judge has include access to all previous cases in which a precedent has been set, and a good English dictionary.
Under the literal rule, the judge should do what the actual legislation states rather than trying to do what the judge thinks that it means. The judge should use the plain everyday ordinary meaning of the words, even if this produces an unjust or undesirable outcome. A good example of problems with this method is R v Maginnis (1987) in which several judges found several different dictionary meanings of the word "supply". Another example might be Fisher v Bell, where it was held that a shopkeeper who placed an illegal item in a shop window with a price tag did not make an offer to sell it, because of the specific meaning of "offer for sale" in contract law. As a result of this case, Parliament amended the statute concerned to end this discrepancy.
The golden rule is used when use of the literal rule would obviously create an absurd result. The court must find genuine difficulties before it declines to use the literal rule. There are two ways in which the Golden Rule can be applied: the narrow method, and the broad method. Under the narrow method, when there are apparently two contradictory meanings to a word used in a legislative provision or it is ambiguous, the least absurd is to be used. For example, in Adler v George (1964), the defendant was found guilty under the Official Secrets Act of 1920. The court chose not to accept the wording literally. Under the broad method, the court may reinterpret the law at will when it is clear that there is only one way to read the statute. This occurred in Re Sigsworth (1935) where a man who murdered his mother was forbidden from inheriting her estate, despite a statute to the contrary.
The mischief rule is the most flexible of the interpretation methods. Stemming from Heydon's Case (1584), it allows the court to enforce what the statute is intended to remedy rather than what the words actually say. For example, in Corkery v Carpenter (1950), a man was found guilty of being drunk in charge of a carriage, although in fact he only had a bicycle.
In the United States, the courts have stated consistently that the text of the statute is read as it is written, using the ordinary meaning of the words of the statute.
Although inferior courts are bound in theory by superior 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 obey precedent might not occur, however, as the expense of an appeal may prevent the losing party from doing so. Thus the inferior court decision may remain in effect even though it does not obey the superior 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 in 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 being judged was already decided by a higher court. Note that inferior courts cannot evade binding precedent of superior courts, but a court can depart from its own prior decisions.
In the United States, stare decisis can interact in counterintuitive 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 required normally to defer to the precedents of intermediate state courts as well.
Courts may choose to obey precedents of international 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 obeyed 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 systems, because it violates the principle that only the legislature may make law. However, the civil law system does have jurisprudence constante, which is similar to Stare decisis and dictates that the Court's decision condone a cohesive and predictable result. In theory, inferior courts are generally not bound to precedents established by superior courts. In practice, the need for predictability means that inferior courts generally defer to precedents by superior courts. In a sense, the most superior 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 jurisprudence constante also influences how court decisions are structured. In general, court decisions of 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 for future cases.
By contrast, court decisions in some civil law jurisdictions (most prominently France) 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 theoretical 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 is done by academic jurists which provide the explanations that in common law nations would be provided by the judges themselves.
In other civil law jurisdictions, such as the German-speaking countries, court opinions tend to be much longer than in France, and courts will frequently cite previous cases and academic writing. However, some courts (such as German courts) have less emphasis on the particular facts of the case than common law courts, but have more emphasis on the discussion of various doctrinal arguments and on finding what the correct interpretation of the law is.
Originalism — the doctrine that holds that the meaning of a written text must be applied — is in tension with stare decisis, but is not necessarily opposed irrevocably. As noted above, "Stare decisis is not usually a doctrine used in civil law systems, because it violates the principle that only the legislature may make law"; Justice Antonin Scalia argues in A Matter of Interpretation that America is a civil law nation, not a common law nation. By principle, originalists are generally unwilling to defer to precedent when precedent seems to come into conflict with the Constitution. However, there is still room within an originalist paradigm for stare decisis; whenever the plain meaning of the text has alternative constructions, past precedent is generally considered a valid guide, with the qualifier being that it cannot change what the text actually says.
Some originalists may be even more extreme. In his confirmation hearings, Justice Clarence Thomas answered a question from Senator Strom Thurmond, qualifying his willingness to change precedent in this way:
Possibly he has changed his mind, or there are a very large body of cases which merit "the additional step" of ignoring the doctrine; according to Scalia, "Clarence Thomas doesn't believe in stare decisis, period. If a constitutional line of authority is wrong, he would say, let’s get it right."
Professor Caleb Nelson, a former clerk for Justice Thomas and law professor at the University of Virginia, has elaborated on the role of stare decisis in originalist jurisprudence:
During 1976, Richard Posner and William Landes invented the term "super-precedent," in an article they wrote about testing theories of precedent by counting citations. Posner and Landes used this term to describe the influential effect of a decision cited.
While Posner and Landes' idea did not become popular, the term "super-precedent" has subsequently become synonymous with a different idea: the difficulty of overturning a decision. During 1992, Rutgers professor Earl Maltz criticized the Supreme Court's decision in Planned Parenthood v. Casey for endorsing the idea that if one side can control the Court on an issue of major national importance (as in Roe v. Wade), then that side can protect its position from being reversed "by a kind of super-stare decisis." The controversial idea that some decisions are virtually immune from being overturned, regardless of whether they were decided correctly in the first place, is the idea to which the term "super stare decisis" now usually refers.
The concept of super-stare decisis (or “super-precedent”) was mentioned during the interrogations of Chief Justice John Roberts and Justice Samuel Alito before the Senate Judiciary Committee. Prior to the commencement of the Roberts hearings, the chair of that committee, Senator Arlen Specter of Pennsylvania, wrote an op/ed in the New York Times referring to Roe as a "super-precedent." He revisited this concept during the hearings, but neither Roberts nor Alito endorsed the term or the concept.
Lastly, super-stare decisis may be considered as one extreme of a range of precedential power.
There is much discussion about the virtue or irrationality of using case law in the context of stare decisis. Supporters of the system, such as minimalists, argue that obeying precedent makes decisions "predictable." For example, a business person can be reasonably assured of predicting a decision where the facts of his or her case are sufficiently similar to a case decided previously. However, critics argue that stare decisis is an application of the argument from authority logical fallacy and can result in the preservation and propagation of cases decided wrongly. Another argument often used against the system is that it is undemocratic as it allows unelected judges to make law. A counter-argument (in favor of the concept of stare decisis) is that if the legislature wishes to alter the case law (other than constitutional interpretations) by statute, the legislature is empowered to do so. Critics sometimes accuse particular judges of applying the doctrine selectively, invoking it to support precedents which the judge supported anyway, but ignoring it in order to change precedents with which the judge disagreed.
Regarding constitutional interpretations, there is concern that over-reliance on the doctrine of stare decisis can be subversive. An erroneous precedent may at first be only slightly inconsistent with the Constitution, and then this error in interpretation can be propagated and increased by further precedents until a result is obtained that is greatly different from the original understanding of the Constitution. Stare decisis is not mandated by the Constitution, and if it causes unconstitutional results then the historical evidence of original understanding can be re-examined. In this opinion, predictable fidelity to the Constitution is more important than fidelity to unconstitutional precedents. See also the living tree doctrine.
Some instances of disregarding precedent are almost universally considered inappropriate. For example, in a rare showing of unity in a Supreme Court opinion discussing judicial activism, Justice Stevens wrote that a circuit court "engaged in an indefensible brand of judicial activism" when it "refused to follow" a "controlling precedent" of the Supreme Court. The rule that lower courts should abide by controlling precedent, sometimes called "vertical precedent," can safely be called settled law. It appears to be equally well accepted that the act of disregarding vertical precedent qualifies as one kind of judicial activism. "Horizontal precedent," the doctrine requiring a court "to follow its own prior decisions in similar cases," is a more complicated and debatable matter....[A]cademics argue that it is sometimes proper to disregard horizontal precedent. Professor Gary Lawson, for example, has argued that stare decisis itself may be unconstitutional if it requires the Court to adhere to an erroneous reading of the Constitution. "If the Constitution says X and a prior judicial decision says Y, a court has not merely the power, but the obligation, to prefer the Constitution." In the same vein, Professors Ahkil Amar and Vikram Amar have stated, "Our general view is that the Rehnquist Court's articulated theory of stare decisis tends to improperly elevate judicial doctrine over the Constitution itself." It does so, they argue, "by requiring excessive deference to past decisions that themselves may have been misinterpretations of the law of the land." For Lawson, Akhil Amar, and Vikram Amar, dismissing erroneous horizontal precedent would not be judicial activism; instead, it would be appropriate constitutional decisionmaking.---Walton Myers