Obiter dictum (plural obiter dicta, often referred to simply as dicta or obiter) is Latin for a statement "said in passing". An obiter dictum is a remark or observation made by a judge that, although included in the body of the court's opinion, does not form a necessary part of the court's decision. In a court opinion, obiter dicta include, but are not limited to, words "introduced by way of illustration, or analogy or argument."[1] Unlike the rationes decidendi, obiter dicta are not the subject of the judicial decision, even if they happen to be correct statements of law. Under the doctrine of stare decisis, statements constituting obiter dicta are therefore not binding, although in some jurisdictions, such as England and Wales, they can be strongly persuasive.
An example of an instance where a court opinion may include obiter dicta is where a court rules that it lacks jurisdiction to hear a case or dismisses the case on a technicality. If the court in such a case offers opinions on the merits of the case, such opinions may constitute obiter dicta. Less clear-cut instances of obiter dicta occur where a judge makes a side comment in an opinion to provide context for other parts of the opinion, or makes a thorough exploration of a relevant area of law. Another example would be where the judge, in explaining his ruling, provides a hypothetical set of facts and explains how he or she believes the law would apply to those facts.
In reaching decisions, courts sometimes quote passages of obiter dicta found in the texts of the opinions from prior cases, with or without acknowledging the quoted passage's status as obiter dicta. A quoted passage of obiter dicta may become part of the holding or ruling in a subsequent case, depending on what the latter court actually decided and how that court treated the principle embodied in the quoted passage.
Obiter dicta can be influential. One example in United States Supreme Court history is the 1886 case Santa Clara County v. Southern Pacific Railroad. A passing remark from Chief Justice Morrison R. Waite, recorded by the court reporter before oral argument, now forms the basis for the doctrine that juristic persons are entitled to protection under the Fourteenth Amendment. Whether or not Chief Justice Waite's remark constitutes binding precedent is arguable, but subsequent rulings treat it as such.
In other instances, obiter dicta can suggest an interpretation of law that has no bearing on the case at hand but might be useful in future cases. The most notable instance of such an occurrence is the history of the famous Footnote 4 to United States v. Carolene Products Co. (1938), which while rejecting use of the Due Process Clause to block most legislation suggested that the clause might be applied to strike down legislation dealing with questions of "fundamental right." This obiter dictum is generally considered to have led to the doctrine of strict scrutiny (and subsequently intermediate scrutiny) in racial-, religious-, and sexual-discrimination cases, first articulated in Korematsu v. United States (1944).
The arguments and reasoning of a dissenting opinion also constitute obiter dicta. These, however, might also be cited should a court determine that its previous decision was in error, as when the United States Supreme Court cited Justice Oliver Wendell Holmes, Jr.'s dissent in Hammer v. Dagenhart when it overturned Hammer in United States v. Darby Lumber Co.