An exhaustive analysis of changes related to the modern law reveals a radicalization of contingency that hugely impacts upon the autonomy of the legal system. The possibility of such a radicalization is the constitutive element of the doctrine of constituent power. Based on a review of the modern constitutionalism’s semantics, particularly in the case of the Abbey Sieyès’s contributions, the conception of a founding power emerges, which can break up any existing political and legal institutions in order to replace them with new political structures. This gives rise to discontinuities of crucial relevance, in which (political) decisions, free from constraints depending on the existing law, can involve even those legal principles at the basis of the entire legal order. In this sense, the constituent power is a mechanism that generates the constitution as its historically specific form, but he simultaneously transcends the latter. Within the dynamics concerning the differentiation of the legal and political system, the constitution functions as an indispensable form of their reciprocal coordination. On the other hand, the political demand underlying the constituent power is responsible for a latent asymmetry with respect to the equilibria between the legal and political system, insofar as the constituent power manifests itself as a potential source of extra-legal transformation to generate new legal structures.
Keywords: Constitutionalism - Constitution - Constituent power - Legal system - Political system