The transformations of constitutionalism that occurred after the Second World War represent an unresolved challenge for Legal positivism. According to some authors, the very meaning of these changes is that the core postulates of Legal positivism (law as a product of human will and the distinction between law and morality) have failed. Consequently, according to such scholars as Atienza, Ruiz Manero and Alexy, this current of thought has lost all its explanato-ry capacity, and it should therefore be abandoned in order to embrace another one. The aim of this essay is to examine these theses, especially Atienza’s, also by highlighting the post-war crisis of Legal positivism, and finally argue that a renewed Legal positivism, in the light of rigid constitutionalism, is, in any case, a theory against any forms of - more or less veiled - Natural Law, which is able to account for today’s legal experience.
Keywords: Legal Positivism Crisis - Second World War - Constitutional Rule of Law - Legal Postposi-tivism