Direito à tributação justa: conteúdo e efeitos do princípio da justiça tributária

Abstract

This doctoral dissertation investigates the meaning, scope, and effects of the principle of tax justice within the Brazilian constitutional system, whose explicit positivization was enacted through Constitutional Amendment No. 132/2023. It is based on the conception that the Constitution represents an open normative political project, whose legitimacy depends on its ability to continuously adjust to the democratic expectations of society. In this context, tax reform is understood as an institutional response to historical deficiencies in the relationship between the tax authority and taxpayers, marked by distrust, opacity, and the absence of a culture of fiscal equity. Justice is treated as a structuring value of the legal system, one that requires normative coherence, equal treatment, and the realization of the rule of law. The dissertation reconstructs tax justice as a constitutional metaprinciple that coordinates other principles—such as ability to pay, equivalence, and progressivity—while guiding, interpreting, and limiting legislative activity in the tax domain. Four legal functions are attributed to this principle: to guide legislative action, to serve as an interpretive standard, to fill normative gaps, and to block rules that are incompatible with equity in the distribution of the tax burden. On this basis, the work examines the origins, foundations, and practical applications of the principles of ability to pay and equivalence, their respective functions in various types of taxes, and the limits of their distributive effectiveness. Extrafiscality is analyzed in its redistributive and behavioral dimensions, demonstrating how it can be reconciled with the demands of tax justice. The analysis of redistributive progressivity is deepened, approached as both a normative mandate and a technique aimed at achieving social justice. It is argued that tax justice requires the harmonization of equal treatment and social equalization, which correspond, respectively, to the objectives of the principles of ability to pay and redistributive progressivity. Adopting a legal-dogmatic methodology, complemented by references to political philosophy and public finance, the dissertation contends that the express constitutionalization of tax justice inaugurates a new paradigm for judicial review of taxation. Although it does not establish a broad subjective right to fair taxation, the principle operates as an objective constitutional norm that constrains legislative discretion and guides the formulation of fiscal policy.Reinforcing this new framework, the principle of non-regressivity was introduced, imposing on the legislature a permanent duty to avoid setbacks in tax justice and to actively reduce the regressive effects of taxation. It constitutes a true guarantee-principle that strengthens the blocking function of the ability-to-pay principle and reinforces the constitutional commitment to tax equity. Promoting tax justice is no longer a mere political aspiration but a legal obligation of the State, supported by normative instruments that enable its effective enforcement.