Os efeitos temporais das decisões do STF em matéria tributária à luz dos princípios da isonomia e da proteção à coisa julgada

Abstract

The Constitutional review in Brazil follows, as a general rule, the nullity theory derived from the American system. According to this theory, a law that conflicts with the Constitution deserves to be extirpated from the legal order, and the legal relations constituted under its regulation need to be disregarded ab initio. Nevertheless, mindful that this model might cause severe violation to the legal certainty and to the public interest, the infra-constitutional legislator has granted to the Brazilian Supreme Court the possibility of not applying the ex tunc effect to the declaration of unconstitutionality, allowing only the forthcoming effects. The debates concerning the temporal modulation of those effects cause even more bustle when the legal relation under judgment is tax-related, as the principle of the res judicata protection comes to a confrontation with the equality of taxpayers one. Under this scenario, it urges to investigate how the above-mentioned principles may be conciliated in order to avoid any unnecessary mutual sacrifices.