Judicial activism and separation of powers: a critical analysis of the Supreme Federal Court's performance in Brazil

Abstract

This paper critically analyzes the phenomenon of judicial activism in Brazil, focusing on the conduct of the Federal Supreme Court (STF) and its impact on the principle of separation of powers. It begins with a historical and theoretical reconstruction of the tripartite division of state functions, from Montesquieu to contemporary constitutionalism, emphasizing the relevance of judicial self-restraint to the preservation of institutional balance. Through bibliographical and documentary research, it distinguishes the concepts of judicialization of politics and judicial activism, examining the growing prominence of the STF in political, social, and institutional matters. Drawing on emblematic cases, such as the “fake news inquiry” and ADO 26, it identifies the main harms attributed to activism: the weakening of the separation of powers, the democratic deficit, legal uncertainty, and the concentration of power within the Court. It concludes that clear institutional limits on constitutional jurisdiction are necessary in order to reconcile the protection of fundamental rights with the preservation of the division of competences and democratic stability.