This paper constitutes a first approach to developing a systematic and comparative study of the institutional Presidency in Latin America. We argue that Latin American presidencies differ from one another not only in the type of institutionalization (what mixture of agencies compose them) but also in the extent to which different ways of informal or personalized presidential support interact with the formal structures. In this paper, we concentrate on two considerably institutionalized Presidencies –those of Argentina and Brazil; we focus on the major agencies that have directly supported the chief of the executive since democratization and develop an analytical framework that captures the variations in terms of the balance of tasks that these agencies perform in the two cases. Then, we search for the explanatory factors that could explain the existing variations. Our hypothesis is that the type of government (either coalition or single-party government) has an impact on the executive’s architecture: we expect more centralization of functions in the first case, as the president must share cabinet positions, negotiate, and manage relations with coalition partners. In single-party governments the president disposes more freely on the whole executive structure, i.e. centralization should be less pronounced. The contrasting types of presidentialism in Brazil and Argentina allow us to test this hypothesis. At last, we conclude showing how the framework could work to analyze further cases.
