Constitutional Adjudication and the Principle of Reasonableness

There is a very close relationship between the Italian Constitutional Court and the principle of reasonableness.¹ The principle of reasonableness expresses the specific character of constitutional adjudication.² All types of review carried out by the Constitutional Court (i.e., the review of statute law and the resolution of disputes between branches of government and between regional and central bodies) imply a review of reasonableness. Reasonableness, when applied to disputes between states, regions, and local governments, translates into the well-known caselaw on interests,³ and when it is applied to disputes between branches of government, it translates into the principle of loyal cooperation.⁴ Moreover, reasonableness is also invoked in judgments on the admissibility of abrogative referendums, which is the least concrete of all types of review. Reasonableness is applied to such referendums through the well-known criterion of homogeneity of the referendum request, as well as through that of proportionality⁵ and that of balancing of constitutional interests.⁶