How do federal dynamics behave in a process of democratic backsliding? This paper discusses a mechanism of the decline of the quality of democracy in a federal country, departing from the argument that federalism and democracy couple in a tense relationship, which could reinforce or hinder each other. The relationship between federalism and democracy is mediated by traditional federal elements, such as the subnational authorities, the party system, and the Upper House, among others. This paper aims to investigate how they act and interact during the process of democratic backsliding, by using process tracing and comparative historical analysis. The causal mechanism is tested in the case of the establishment of dictatorship in Brazil in the 1960s and brings insights into the current Brazilian scenario. The main findings highlight the role subnational authorities can play in the process of democratic backsliding; the features of the party system in that context; and cast doubt on the abilities of the Senate for effective territorial representation within a federation.