Vacatio legis is the legal institute that designates the time interval between the official publication of a rule and its effective entry into force, situated primarily within the scope of the General Theory of Law and Intertemporal Law. Its primary purpose is to ensure legal certainty and the stability of social relations, allowing the recipients of the normative precept and legal practitioners to become aware of the new regulation and promote the necessary adaptations before it becomes mandatory.
1. Definition, Concept, and Legal Nature
The term vacatio legis (vacancy of the law) refers to the dormancy period of a legislative act. From the perspective of legal dogmatics, a legal rule goes through an iter that includes drafting, approval, sanction, promulgation, and publication. However, the validity—the quality of the rule that makes it capable of producing legal effects and demanding obedience—may not coincide chronologically with the date of its publication.
The legal nature of vacatio legis is that of a suspensive condition of effectiveness. Although the law already possesses existence and validity in the legal system from its promulgation and publication, its mandatory nature remains suspended for a period determined by the legislator or by supplementary rules. During this hiatus, the previous law remains in full force, unless otherwise expressly provided, and the new law cannot be invoked to support judicial decisions or administrative acts, except in cases of purely interpretive rules or abolitio criminis in Criminal Law.
2. Historical Origin and Evolution in Law
Historically, the need for an adaptation period dates back to Roman Law, although the systematization of the institute as we know it is a product of modernity and the need for publicity of state acts. In the Brazilian scenario, vacatio legis was initially consolidated in the Introduction to the 1916 Civil Code. With the evolution of legal thought, the regulation was moved to Decree-Law No. 4,657/1942, originally called the Law of Introduction to the Civil Code (LICC) and, as of 2010, renamed the Law of Introduction to the Norms of Brazilian Law (LINDB), by Law No. 12,376/2010.
In Comparative Law, the institute is universally accepted, with only the deadlines and counting methods varying. In France, for example, the Code Civil establishes differentiated deadlines based on publication in the Journal Officiel, while in the Portuguese legal system, the Civil Code also provides for vacancy periods to ensure knowledge of the law (a vacatio legis of five days, if no other period is fixed).
3. Legal Provision and Counting Criteria
The primary legal basis for vacatio legis in Brazil is found in Article 1 of the LINDB and Article 8 of Supplementary Law No. 95/1998. The provisions establish the following rules:
- General Rule (Art. 1, LINDB): Unless otherwise provided, the law begins to be in force throughout the country 45 days after it is officially published.
- International Scope (Art. 1, § 1, LINDB): In foreign states, the mandatory nature of Brazilian law, when admitted, begins three months after it is officially published.
- Setting the Deadline (Art. 8, LC 95/1998): The validity clause must be established precisely. A law that establishes a vacancy period must do so by indicating the number of days, rather than specific dates, to avoid ambiguity.
- Counting the Deadline (Art. 8, § 1, LC 95/1998): The count includes the date of publication and the last day of the period, entering into force on the day following its full completion.
It is imperative to note that if a new publication of the text of the law occurs before it enters into force, aimed at correcting material errors, the vacancy period will begin to run again from the new publication (Art. 1, § 3, LINDB). If the correction occurs in a law already in force, it will be considered a new law (Art. 1, § 4, LINDB).
4. Practical Application and Jurisprudential Understanding
The jurisprudence of the Superior Courts (STF and STJ) has consolidated the understanding that vacatio legis is an instrument for protecting the principle of non-surprise and legitimate expectation.
The Supreme Federal Court (STF), in the context of constitutional review, has stated that the absence of a vacancy period in high-impact laws may, in theory, violate reasonableness, although the legislator has the discretion to determine immediate entry into force ("this law enters into force on the date of its publication"). However, in tax matters, the STF strictly applies the principle of anteriority (nonagesimal and fiscal year), which functions as a specific modality of constitutional vacatio legis (Art. 150, III, 'b' and 'c', CF/88).
The Superior Court of Justice (STJ) has relevant precedents regarding the application of procedural laws. In the judgment of Special Appeal No. 1,411,413/MG, the application of the 2015 Code of Civil Procedure was discussed, reinforcing that procedural acts performed during the vacatio are governed by the old law, but the new law takes over the process in the state it is in at the moment of its entry into force (Theory of Isolated Procedural Acts).
In the Superior Labor Court (TST), the debate was intense during the Labor Reform (Law No. 13,467/2017). The jurisprudence was established in the sense that the vacancy period must be strictly respected, not allowing the retroactive application of rules detrimental to the worker that have been published but are not yet in force.
5. Related Principles and Doctrinal Divergences
The institute dialogues directly with the following principles:
- Principle of Mandatory Laws: No one can excuse themselves from complying with the law by claiming they do not know it (Art. 3, LINDB). The vacatio justifies the absolute presumption of knowledge after the deadline.
- Legal Certainty: Prevents abrupt changes in the legal system that would make planning by the public impossible.
- Non-retroactivity: The rule in vacancy does not retroact to affect the perfect legal act, acquired rights, and res judicata.
Doctrinally, the validity of infralegal normative acts issued during the vacatio to regulate the future law is discussed. The majority view is that such decrees or resolutions may be published, but their effectiveness is conditioned on the entry into force of the parent law.
6. Contemporary Relevance and Impacts on the Legal System
Recently, vacatio legis has assumed a central role in structural reforms. The General Data Protection Law (LGPD - Law No. 13,709/2018) had a complex schedule of entry into force, with distinct vacancy periods for main obligations and administrative sanctions, aimed at allowing the technological adaptation of companies.
Likewise, the New Bidding Law (Law No. 14,133/2021) established a two-year transition period, during which it coexisted with previous laws (Law 8,666/93 and Law 10,520/02). This model of "optional vacancy" or normative coexistence demonstrates the evolution of the institute toward more flexible forms of legal transition in complex systems.
In short, vacatio legis is not just an inert lapse of time, but a space for democratic transition that ensures that legislative change does not turn into arbitrariness, respecting the capacity of citizens and institutions to adapt to state commands.
Legal and Jurisprudential References
- BRAZIL. Decree-Law No. 4,657, of September 4, 1942. Law of Introduction to the Norms of Brazilian Law.
- BRAZIL. Supplementary Law No. 95, of February 26, 1998. Provides for the drafting, wording, alteration, and consolidation of laws.
- BRAZIL. Constitution of the Federative Republic of Brazil of 1988. Art. 150 (Tax Anteriority).
- STF. ADI 4,167/DF. Rapporteur Justice Joaquim Barbosa. Judgment on the effectiveness of rules and implementation deadlines.
- STJ. REsp 1,411,413/MG. Rapporteur Justice Mauro Campbell Marques. Second Section. Topic: Intertemporal Law and CPC/2015.
- STJ. Precedent 543 (by analogy of temporal application in contracts).
