"In Brazil, even the past is uncertain." The phrase, whose authorship is attributed to both the former President of the Central Bank Gustavo Loyola and the former minister Pedro Malan, summarizes the action of the Supreme Court (STF) on February 8, by not applying the modulation of effects on the cessation of the effectiveness of the res judicata in tax matters.

Regardless of the specific tax issues of the judges, a point that drew attention concerns the possibility of automatic cessation of the effect of the res judicata from the weighting of constitutional principles and values at stake, with a departure from any modulation of the effects of the declaration of constitutionality/unconstitutionality, not only for reasons of legal certainty or exceptional social interest –^[1]  which could "authorize" the extension of this understanding to cases involving successive treaty obligations from several other areas.

Before addressing this issue specifically, it is important to remember the developments so far settled in the Supreme Court on the declaration of constitutionality or unconstitutionality of a rule.

The effectiveness of the declaration of constitutionality/unconstitutionality is divided into two species:

• normative effectiveness, related to the maintenance or exclusion of a certain normative precept of the legal system; and
• effectiveness, corresponding to the attribution of imposing force in relation to supervening acts.

In the judgment of RE 730.462 (Theme 733 of the general repercussion), of rapporteurs of the late Minister Teori Zavascki, the Supreme Court recognized that "the decision of the Supreme Court declaring the constitutionality or unconstitutionality of normative precept does not produce the automatic reform or termination of previous judgments that have adopted different understanding; for this to occur, it will be indispensable to file its own appeal or, if applicable, the purpose of the own termination action, pursuant to Art. 485, V, of the CPC, observing the respective period of procedure (CPC, art. 495)".^[2]

The reason behind the above understanding is that, once the  court decision is given observing the criteria provided for it to be considered valid (presenting one of the possible interpretations for the provisions applicable to the case), this will reflect an act of application of the law and, therefore, an individual and concrete rule, whose scope is to discipline the legal relationship between the subjects who have integrated the poles of the demand. Although the Brazilian system of precedents provides for situations in which the decision resulting from the judgment of some instruments has a binding effect, it cannot be denied that, in order to have the ability to regulate a particular legal relationship, it is essential that the understanding to be followed is reflected in an individual and concrete norm.

However, the scenario so far sedimented^[3] seems to have changed in recent weeks, from the judgment of RE 949.297 and RE 955.227.

This is because the judges define whether and how the decisions of the Supreme Court cease the future effects of the res judicata in tax matters, when the decision, with declaratory effects, is based on the constitutionality or unconstitutionality of a tax.

To exemplify, it is considered that a company X questions the collection of a certain tax by the Union. After obtaining a favorable decision, having become final, it ceases to pay the extradition. Subsequently, the Supreme Court decides on the constitutionality of the collection of the tax in concentrated or diffuse control with general repercussion.

What are the effects of this subsequent pronouncement of the Supreme Court in relation to the taxpayer who is the owner of the thing deemed to be excluded from the collection of the tax?  Is it still producing effects? Can it be reconstituted via rescission action? Do its effects cease from the conclusion of the judgment by the Supreme Court in concentrated or diffuse control of constitutionality nthe rite of general repercussion?

In the recent trial by the Supreme Court, the third option prevailed.  This means that, not atthe time when the Supreme Court decides for the constitutionality of the collection of the tax (in the specific case, this happened in 2007, through ADI), the res judicata that the taxpayer had ceases to produce effects for the future, regardless of the judgment of rescission action.  An observation was made: only the automatic cessation of  the effectiveness of the res judicata will occur when the subsequent decision of the Supreme Court was made in concentrated or diffuse control and concrete constitutionality according to the rite of general repercussion.

This understanding is based on two main grounds expressed in the Supreme Court's decision:

• "if it would be producing tax and economic injustice, because modulation in favor of those who, even knowing the very clear position of the Supreme Court, still persisted in not collecting"; and
• "the maintenance of final decisions that declare the unconstitutionality of the incidence of the Social Contribution on Net Income (CSLL) – in reaction to generating events after that year – reveals discrepancies that could violate tax equality in the face of unequal treatment as well as free competition. This is because the taxpayer exempted from the payment of tax by final decision has a competitive advantage over the others, since it does not allocate a portion of its resources for this purpose – a situation different from that of its competitors who are obliged to pay – in order to cheapen the costs of its structure and production."

Clearly, the Supreme Court has put in front of constitutional principles and values, to decide not only on the modulation or not of the effects of the declaration of constitutionality, but also to recognize the possibility of automatic cessation of the effectiveness of the res judicata. In the specific case, we have a clash. On the one hand, legal certainty (judged) on the other hand, equality and free competition.

One aspect that drew much attention, in a negative way, was the non-modulation of the effects of the decision and, therefore, the attribution of retroactive effects to the new understanding. Until the trial of the 949,297 RE and the 955,227 RE, the jurisprudence of the Supreme Court recognized that the res judicata would only have its effectiveness impeded if there was a rescission action, even though the position reflected in it was not in tune with the supervenient position of the Court (General rebound theme 733).

With the 2015 CPC edition, Article 927, § 3, was introduced^[4], which contains a wording similar to article 27 of Law 9,868/99, which authorizes the Supreme Court to modulate the effects of its decisions provided that its jurisprudence changes or in judgment of repetitive appeals. The reason for justifying the modulation of the effects should be social interest and legal certainty. And here, we are drawn to the fact that the decision to be modulated is no longer required to be that which has declared the unconstitutionality of a legal act or a normative act. The parameter becomes the case law of the court or the projustice of a decision in the judgment of repetitive appeals.

In any case, the premise is the existence of an understanding with broad scope and whose modification allows you to affect a significant number of legal relations, a reason that allows the effects of the decision to be calibrated, with the establishment of a specific moment from which the new interpretation should be observed.

to allow retroactive effects to the decision amending dominant case-law, such as that arising from the judgment of 949,297 RE and the 955,227 RE is an affront to legal certainty, in particular because taxpayers who behaved over many years according to the res judicata on their ownership have complied with valid, effective determinations in force emanating from the Judicial.

However, many years later, the same judiciary decides that those decisions should not take effect, even if those concerned have not used the instruments that the procedural system makes available to challenge decisions that have become final.

We have not reduced the importance of the primacy of isonomy and free competition, but it is extremely dangerous to sanction taxpayers who have behaved in accordance with a decision issued by the judiciary and which has set the limits of their legal relationship with the Union with regard to a specific tax.  Therefore, even if the cessation of the effectiveness of the res judicata by virtue of a retrial with binding force is authorized, the protection of legal certainty requires that the acts carried out in accordance with an order emanating from the judiciary itself be preserved, determining that the new orientation should apply for the future.

That is, there is a real innovation of the rule on the institute of the res judicata provided for in Article 502 of the Code of Civil Procedure, by admitting the  possibility of breaking its effectiveness from  the weighting of constitutional values, moving away from the need for employment from the rescission action.

Although the precedents discussed by the Supreme Court concern the  tax obligation of successive treatment, nothing prevents issues of this kind from other areas may suffer impacts (  for example, administrative or civil contracts of successive treatment that have constitutional repercussion, able to attract the jurisdiction of the Supreme Court to resolve any conflict)  . At this point lies the concern of all operators of the right to follow the future consequences of this decision, since its orientation may affect legal relations of various branches.

^[1] As recommended in Article 27 of Law 9,868/99 and Article 535, §6, of the CPC.

^[2] According to the opinion of Minister Teori Zavascki: "Normative effectiveness (= declaration of constitutionality or unconstitutionality) operates ex tunc, because the judgment of validity or nullity, by its nature, is directed to the very birth of the rule questioned. However, when it comes to executive effectiveness, it is not correct to say that it has been effective from the origin of the standard. It is that the binding effect, which supports it, does not stem from the validity or invalidity of the rule examined, but from the judgment examining it.

Deriving, the executive effectiveness, from the judgment (and not from the validity of the rule examined), its initial term is the date of publication of the judgment of the Supreme in the Official Gazette (art. 28 of Law 9.868/99). It is therefore effective that it achieves administrative acts and judicial decisions supervening to that publication, not previous acts. Previous acts, even when formed on the basis of an unconstitutional rule, can only be undone or terminated, if applicable, in their own process."

^[3] We cannot fail to bring to debate the provisions of Article 535, §§ 5 to 8 of the CPC, which also considers unenforceable the obligation recognized in judicial enforcement order founded on law or normative act considered unconstitutional by the Supreme Court, or founded on application or interpretation of the law or normative act taken by the Supreme Court as incompatible with the Federal Constitution,  concentrated or diffuse constitutionality control.

In addition, it authorizes that the effects of the decision of the Supreme Court can be modulated in time to promote legal certainty. Finally, it specifies that, if the decision is given after the final judgment of the decision under execution, it will be up to the rescission, the period of which will be counted from the final judgment of the decision given by the Supreme Court.

It is quite true that this provision deals with the declaration of unconstitutionality of the rule. However, for the sake of symmetry, it cannot be ruled out in cases of a certain enforcement order becoming inadmissible even if by the declaration of constitutionality of the rule, especially in the case of the specific case under that article, since the recipient undertakings had an enforcement order on an obligation not to pay in a successive agreement.

^[4] Art. 927. Judges and courts shall observe:

• 3 - In the event of a change in the dominant case law of the Supreme Federal Court and the higher courts or that arising from the judgment of repetitive cases, there may be modulation of the effects of the change on the social interest and legal certainty.