the case of the Serrano Cruz Sisters versus El Salvador (Judgment on preliminary objections of 11.23.2004).119 148. In a new stage of its jurisprudential construction in this regard, the Court went even further, by expanding the material content of the jus cogens in its historical Advisory Opinion n. 18 (of 09.17.2003), on the Juridical Condition and Rights of the Undocumented Migrants, thus including the basic principle of equality and nondiscrimination (paras. 97-101 and 110-111).120 Regarding this other great parallel jurisprudential step forward I issued an extensive Concurring Opinion (paras. 1-89), in which I supported the Court’s position, acknowledging that this basic principle permeates the entire legal system, and requesting attention to its importance and that of all the general principles of law, from which the rules and regulations arise, and without which, in the end, there is no “legal system " (paras. 44-46 and 65).121 149. Since then, I went on to insist, within the Court, in successive contentious cases, on the need to expand even more the material content of the jus cogens, so . 119 Paras. 2, 32, and 39-41 of the Opinion. . The IACHR held that the States have the duty to respect and guarantee respect for human rights in the light of the general and basic principle of equality and non-discrimination, and that any discriminatory treatment with regard to the protection and exercise of said rights (even labor ones) generates the States’ international responsibility. In the Court’s understanding, the mentioned fundamental principle entered the sphere of the jus cogens, thus not allowing the States to discriminate or tolerate discriminatory situations, in detriment of migrants, and having to guarantee the due process of law to any person, regardless of their migratory status. The States cannot subordinate or condition the observance of the principle of equality before the law and non-discrimination to the objectives of immigration policies, among others. 120 . In syntheses, said principles make up, in my understanding, the substratum of the legal system itself (paras. 52-58). The matters covered by me – including the evolution of the jus cogens and of the obligations erga omnes of protection, - was done within the realm of the definition of the civitas maxima gentium and of the universality of human gender. In a stretch of my mentioned Concurring Opinion, I allowed myself to consider that "Every legal system has fundamental principles, which inspire, inform and conform their norms. It is the principles (derived ethmologically from the Latin principium) that, evoking the first causes, sources or origins of the norms and rules, confer cohesion, coherence and legitimacy upon the legal norms and the legal system as a whole. It is the general principles of law (prima principia) which confer to the legal order (both national and international) its ineluctable axiological dimension; it is they that reveal the values which inspire the whole legal order and which, ultimately, provide its foundations themselves. This is how I conceive the presence and the position of the principles in any legal order, and their role in the conceptual universe of Law. From the prima principia the norms and rules emanate, which in them find their meaning. The principles are thus present in the origins of Law itself. The principles show us the legitimate ends to seek: the common good (of all human beings, and not of an abstract collectivity), the realization of justice (at both national and international levels), the necessary primacy of law over force, the preservation of peace. Contrary to those who attempt - in my view in vain - minimize them, I understand that, if there are no principles, nor is there truly a legal system. Without the principles, the "legal order" simply is not accomplished, and ceases to exist as such. (...)." (paras. 44 and 46) 121