The constitutional state of law is characterized by the incorporation of a set of principles whose structure differs from the rules as. They don’t have defined the obligation to charge in case of infringement. The presence of these principles represents an increase of discretion, as the power to determine the meaning of legal statements must be limited as a basic rule of law in which any expression of power must be constrained by a rule of law. In this context the principles have a dimension of weight assumed by a sector of the doctrine as a limit on the dis- cretion and by another as the unrestricted exercise of the same. The decision in favor of either position depends on the recognition of the changing legal theory in the context of the constitutional state and, especially, the notion of principles to be adopted (moral or legal principles).