This essay starts from a depiction of the crisis of the liberal legal State in accordance with the theses of Romano and Capograssi, and then identifies the distinctive features of the constitutional State: the sovereignty of the constitution as, first, the foundation of rights, the value of jurisdiction in implementing the costitution, and the supranational dimension of protection of fundamental rights. At the same time, the article emphasizes the passage “from the individual to the person”. The constitutionalization of the person, considered in his concrete needs, refers to the concept of human dignity and its ability for effective integration from the social, economic and political points of view. Human dignity, although a supreme principle, mantains an indefinite character, with many conflicting applications. The topics in favour of its protection naturally belong to the tenets of practical reason, and reasonableness especially.