Multidimensional Theory of Tax Justice

Abstract

This article proposes a classification of the dimensions of tax justice as a contribution to the debate on the normative content of this principle, particularly considering its explicit constitutionalization by Constitutional Amendment No. 132/2023. It argues that tax justice is not a one-dimensional principle and that its realization requires recognizing multiple planes on which it operates. Thirteen dimensions are identified and organized into two groups. The first comprises six defensive dimensions that function as limits and guarantees against taxation: the limit on the tax burden; its distribution; the constitutional limitations on the power to tax; the substantive protection of taxpayers against excessive taxation; the procedural dimension; and the simplicity and transparency of the system. The second contemplates seven functional dimensions, related to the requirements for taxation to fulfill its constitutional purposes: the effectiveness of taxation, the generality of taxation and the control of tax expenditures, the legitimizing financial dimension, the overcoming of structural inequalities, the budgetary financial dimension, federative justice, and inter-nation equity. The article argues that the Brazilian tax tradition, formed under authoritarian influence and marked by a defensive reading of the relationship between tax authorities and taxpayers, has systematically underestimated the functional dimensions, and that recognizing the multidimensional character of tax justice is a condition for the principle to transcend rhetoric and become an effective instrument for the control and orientation of the National Tax System.