2021-12-172021-12-172021-12-172021-12-12https://ri.ucsal.br/handle/prefix/4717This article will seek to promote a critical analysis of the Supreme Court's Judicial Activism in the search for the effectiveness of constitutional norms, its proactive performance in the exercise of atypical and original functions of the Executive and Legislative Powers, in the preservation of the Democratic State of Law. In the foreground, portray the impact of this expansive performance by the Extraordinary Court, demonstrating the positive and negative points of this performance. In the background, through a methodology of descriptive and analytical nature, in view of the need to examine the Brazilian political and legal situation, it will address some very pertinent STF decisions, with the aim of helping to understand the topic addressed. Finally, at the end of this article, to establish a critical view of the fine line between the Supreme Court's Judicial Activism, the preservation of Fundamental Guarantees and the violation of the Principles of Legality and Separation of Powers.Acesso AbertoAtivismo judicialSupremo tribunal federalGarantias fundamentaisLegalidadeSeparação dos poderesJudicial activismFederal court of justiceFundamental guaranteesLegalitySeparation of powersTrabalho de Conclusão de CursoCiências Sociais AplicadasDireito