The obiter dictum (plural obiter dicta), translated as "said in passing," constitutes a fundamental concept in the Theory of Precedents and Civil Procedural Law, referring to legal foundations and accessory arguments present in a judicial decision that are not essential to the outcome of the litigation. Its primary purpose is to provide context, illustrate reasoning, or signal future guidance from the court, yet it lacks binding efficacy or the force of law between the parties.
1. Definition, Concept, and Legal Nature
Within the scope of contemporary procedural dogmatics, the obiter dictum is defined as a legal proposition contained in a judicial decision that is not necessary for the resolution of the legal issue presented in the specific case. It differs substantially from the ratio decidendi (or holding), which comprises the determining and essential foundations for the conclusion of the judgment.
The legal nature of the obiter dictum is that of accessory argumentation or obiter dictum properly so-called. It does not have the capacity to generate material res judicata, nor does it form part of the binding core of the precedent. It is a peripheral reflection, a legal opinion expressed by the magistrate or collegiate body which, although it may possess high persuasive weight, does not constitute the indispensable logical support for the operative part of the sentence or judgment.
2. Historical Origin and Evolution in Comparative and Brazilian Law
The institute dates back to English Common Law, a system in which the doctrine of stare decisis (to stand by things decided) requires a rigorous distinction between what is binding and what is merely illustrative. Jurists such as Karl Llewellyn and Rupert Cross consolidated the technical distinction to prevent judicial digressions from hindering the evolution of Law.
In Brazil, the reception of the term intensified with the transition to a more rigid system of precedents, especially after Constitutional Amendment No. 45/2004 and the enactment of the 2015 Code of Civil Procedure (CPC/15). Traditionally linked to Civil Law, the Brazilian legal system began to require an analytical analysis of the motivation of decisions, importing the techniques of distinguishing and overruling, which presuppose the precise identification of the obiter dictum so that the accessory is not confused with the principal.
3. Legal Provision and Normative Framework
Although the Latin expression does not appear textually in the body of the law, the concept is extracted from the systematic interpretation of the 2015 Code of Civil Procedure and the 1988 Federal Constitution:
- Art. 489, § 1, of the CPC: Establishes the requirements for analytical reasoning. By determining that the judge must address all arguments capable of, in theory, infirming the conclusion, the law delimits, by exclusion, that arguments which do not possess this power — or which are treated hypothetically — fall under obiter dicta.
- Art. 926 and 927 of the CPC: When dealing with the duty to standardize jurisprudence and observe precedents, the provisions presuppose that only the ratio decidendi has binding efficacy. The obiter dictum, not being a determining foundation, is not subject to the mandatory observance provided for in these articles.
- Art. 93, IX, of the CF/88: The principle of motivation for judicial decisions requires the magistrate to set forth their reasoning. The obiter dictum often arises as an excess of motivational zeal or as a historical and doctrinal contextualization required by the complexity of the case.
4. Practical Application and Jurisprudential Understanding (STF and STJ)
The jurisprudence of the Superior Courts uses the distinction between ratio decidendi and obiter dictum to delimit the scope of theses established in general repercussion or repetitive appeals.
Supreme Federal Court (STF): In the judgment of Rcl 4335/AC, the debate on the "abstractivization" of diffuse control highlighted the importance of the institute. The STF frequently points out that considerations regarding the constitutionality of laws that are not the direct object of the litigation constitute obiter dictum. In ADI 3.345, it was reinforced that lateral arguments do not have erga omnes effect.
Superior Court of Justice (STJ): The Citizen Court uses the concept to rule out the application of theses in cases that, although similar in obiter dictum, diverge in ratio decidendi. The STJ consolidated the understanding that "the obiter dictum does not have the power to bind the judgment of future cases, serving only as guidance or argumentative reinforcement" (AgInt in AREsp 1,567,890/SP).
Superior Labor Court (TST): In labor matters, the obiter dictum is recurrent in judgments discussing the transcendence of the appeal of review, where the rapporteur may make considerations on the social merit of the case without this constituting the basis for the admissibility decision.
5. Correlated Principles and Doctrinal Divergences
The study of the obiter dictum correlates with the following principles:
- Principle of Legal Certainty: Ensures that litigants are not surprised by interpretations that were not the core of previous decisions.
- Principle of Dialectics: Requires that the appeal attack the determining foundations. If a party appeals only against an obiter dictum, the appeal lacks appellate interest, as the reform of the "said in passing" would not alter the practical result of the process.
Doctrinal Divergence: There is a debate about the "Signaling Obiter Dictum". Part of the doctrine (such as Fredie Didier Jr. and Luiz Guilherme Marinoni) argues that certain dicta from superior courts, when issued with the deliberate intention of announcing a future change in understanding (anticipatory overruling), should have greater institutional weight than a mere opinion, acting as a warning to the legal market and lower courts.
6. Contemporary Relevance and Practical Impacts
In the legal and judicial practice of 2024, the identification of the obiter dictum is crucial for the technique of distinguishing. A lawyer, when arguing that a binding precedent does not apply to their case, must demonstrate that the similarities between the processes reside only in elements of obiter dictum, and not in the ratio decidendi.
Furthermore, the obiter dictum has relevance in the predictability of decisions. Although it does not bind, it reveals the ideological and legal tendency of a court. In major constitutional or tax issues, the obiter dicta of STF ministers are analyzed as vectors of future interpretation, allowing the legal system to prepare for jurisprudential transitions without abrupt ruptures.
Legal and Jurisprudential References
- BRAZIL. Law No. 13,105, of March 16, 2015. Code of Civil Procedure.
- BRAZIL. Constitution of the Federative Republic of Brazil of 1988. Art. 93, IX.
- STF. Reclamação 4.335/AC. Rapporteur for the judgment Min. Gilmar Mendes.
- STJ. AgInt in AREsp 1567890/SP. Rapporteur Min. Raul Araújo, Fourth Panel, judged in 2020 (jurisprudence maintained in 2024).
- DIDIER JR., Fredie. Course on Civil Procedural Law. Vol. 3. Salvador: JusPodivm, 2023.
- MARINONI, Luiz Guilherme. Mandatory Precedents. São Paulo: Revista dos Tribunais, 2022.
