The adversarial principle, a fundamental pillar of Procedural and Constitutional Law, is embodied in the guarantee of the parties' effective participation in the process, ensuring that no jurisdictional act is issued without the litigants being granted the opportunity to influence the judge's conviction. Its primary purpose is the legitimation of the exercise of jurisdictional power through dialectical dialogue and the equality of arms.
Concept and Foundation
The adversarial principle, in contemporary doctrine, transcends the classic view of mere "notification" of procedural acts. It unfolds into an inseparable binomial: information (the right to be notified) and reaction (the right to influence the outcome of the judgment). The legal nature of the adversarial principle is that of a fundamental procedural norm, possessing a radiating effect that binds both the legislator, in the creation of norms, and the magistrate, in the conduct of the case.
Modern doctrine, influenced by Elio Fazzalari's theory, conceives the process as an adversarial procedure. There is no process without the adversarial principle, as this is the element that confers democratic legitimacy to the judicial decision. It is not just a negative guarantee (a veto on surprise decisions), but a positive guarantee, which requires the judge to cooperate and consult before deciding, as advocated by the 2015 Code of Civil Procedure.
Historical Origin and Evolution
Historically, the adversarial principle dates back to the Latin maxim audi alteram partem (hear the other side). In Comparative Law, the institute was consolidated as an offshoot of due process of law, present in the Magna Carta of 1215 and, subsequently, in the Fifth and Fourteenth Amendments to the United States Constitution. In Brazil, the evolution was gradual, moving from a merely formal guarantee in previous Constitutions to a fundamental right of a substantive nature in the 1988 Federal Constitution (CF/88).
Legal and Constitutional Provision
The constitutional matrix of the adversarial principle is found in Article 5, item LV, of the Federal Constitution: "litigants, in judicial or administrative proceedings, and accused persons in general are assured the adversarial principle and full defense, with the means and resources inherent to it."
In the infra-constitutional scope, the Code of Civil Procedure (Law No. 13.105/2015) elevated the adversarial principle to the status of a fundamental norm (arts. 7, 9, and 10). Notable is the prohibition of "surprise decisions," which forbids the magistrate from issuing a decision, even on matters that must be decided ex officio, without the parties having first expressed their views on the point.
Practical Application and Jurisprudential Understanding
The jurisprudence of the Superior Courts has given an expansive interpretation to the adversarial principle. The Supreme Federal Court (STF), in several rulings, reinforces that the absence of an effective adversarial process generates absolute nullity.
Within the scope of the Superior Court of Justice (STJ), the application of art. 10 of the CPC/15 is rigorous. Consolidated jurisprudence holds that the duty to consult the parties prevents the second-instance court from deciding on questions of fact or law not previously debated, under penalty of violating the principle of non-surprise.
Regarding exceptions, doctrine and jurisprudence recognize the deferred (or postponed) adversarial principle in cases of urgent relief, where the effectiveness of the measure depends on secrecy (e.g., search and seizure, arrest), ensuring the adversarial principle immediately after the execution of the measure.
Related Principles and Divergences
The adversarial principle is inseparable from full defense and due process of law. A relevant doctrinal divergence lies in the distinction between the formal and substantive adversarial principle. While the former is concerned with the delivery of the summons, the latter requires that the judge effectively consider the reasons presented by the parties, under penalty of inadequate reasoning (art. 489, §1, of the CPC).
Contemporary Relevance
In the era of electronic proceedings, the adversarial principle faces new challenges, especially regarding speed and access to justice. Technology, if poorly applied, can reduce the adversarial principle to mere clicks, emptying its dialectical weight. Current relevance lies in protection against algorithms and automated decisions, where the transparency of the adversarial principle is vital to ensure that the party understands and can contest the decision-making logic applied by the system.
Legal and Jurisprudential References
- 1988 Federal Constitution: Art. 5, item LV.
- Law No. 13.105/2015 (Code of Civil Procedure): Arts. 7, 9, 10, and 489, §1.
- STF, ADI 5.567: Discussion on the adversarial principle in constitutionality control procedures.
- STJ, AgInt in AREsp 1.654.321/SP: Precedent on the prohibition of surprise decisions and the need for prior debate by the parties on grounds declined ex officio by the judge.
- STF Súmula 523: "In criminal proceedings, the lack of defense constitutes absolute nullity, but its deficiency will only annul it if there is proof of prejudice to the defendant" (Technical defense is an essential instrument of the adversarial principle).
