RESUMO O constitucionalismo, enquanto resultado de uma série de movimentos de racionalização do Estado, serviu como indispensável vetor intelectual de limitação do exercício do poder do governante ainda no século XVII, por meio da previsão de direitos e garantias firmados em leis e declarações. Contudo, se antes a sua grande força motriz girava em torno da limitação do poder estatal e da separação de poderes, hoje os problemas são PALAVRAS -CHAVE Diálogo Institucional. Construção Racional dos Direitos nas Democracias. Judicial Review.ABSTRACT Constitutionalism, as a result of a series of state rationalization movements, served as an indispensable intellectual vector, limiting the exercise of the ruler's power in the seventeenth century, specially through the provision of rights and guarantees in laws and declarations. However, if its great driving force used to be the limitation of state power and the separation of powers, today the problems are much more challenging. That's a result of the plurality of interests and rights in today' s societies which has inspired a new political -juridical vision that contemplates institutional arrangements capable of leading to a more democratic exercise of constitutional interpretation, that is, alternatives in which the meaning of rights is result from of a rational construction between the Powers instituted, thus lacking the figure of one supreme branch of government. The theory of Institutional Dialogue, object of the present analysis, is the most remarkable of these new arrangements. Definable, in short, as a system in which major decisions of a constitutional court can be redrawn by a legislative body, it was first adopted by the Canadian constitution in the 1980s, and today has elicited considerable academic debate about its potentials and failures. Thus, the present study, based on an essentially bibliographic and qualitative bias, analyzes the historical and conceptual origin of this theory, seeking to show how power structures can dialogue, and to what extent public dialogue can be present in the system of definition of rights in Portugal.