This paper aims to present a dogmatic model to understand the legal nature of unconstitutional norms and acts and the modulation of the effects of unconstitutionality decisions. To this end, it begins by analysing one of the traditional assumptions of the theory of law of the separation of the planes of the norm and the legal act, examining the idea of nullity of the unconstitutional norm. It then presents two different models for understanding the modulation of effects, pointing to the so-called broad model as the most appropriate for greater clarity and consistency in decision-making, in addition to respect for the quorum legally established for this measure. Finally, groups of cases from the case law of the Federal Supreme Court are examined to identify the impact of the proposed model.