The objective of this paper is to analyze the application of the 'ability to pay' principle to decisions of the Brazilian Supreme Court. In research carried out on the court website, the term 'ability to pay' appeared 70 times in court decisions, until November, 2008. In order to analyze the decisions, I began with texts from Italian jurists, especially Pietro Boria, who sought to demonstrate that the ability to pay principle in Italy is applied both in the protection of taxpayer interests as well as the protection of the state. Decisions were divided into five groups, according to the interest protected and the subject involved. I concluded that, although some times the principle has been applied in the protection of the taxpayer interests, it was almost always applied in the protection of the state interests.
ability to pay; Brazilian Supreme Court; progressivity; equity; interpretation