As we have seen, Vitoria elaborated a theory of universal law based on the assumed rationality of all men (thereby including the Indians), emphasizing, though, the rights to travel, trade and do missionary work to which the Spaniards in America were naturally entitled. Unlike him, las Casas stressed the right to liberty as a foundation for the right to self-determination of the Amerindians, and that clearly put into question the whole process of colonisation. As Barreto writes “The idea of self-determination, defended four hundred years before by Las Casas as a principle of natural right, became positive international law when the struggle for decolonisation triumphed in the ambit of international human rights law.”

Returning to just war, Vitoria conceived it as a right to deprive the Indians of their possessions, keeping them in captivity and setting up new overlords. In the way it existed in Vitoria’s time, international law was not provided with the legal apparatus required to justify the occupation of the “new world” and resolve the question of Spanish-Indian relationship. As Barreto correctly states “The ‘emergence’ of a whole continent triggered immediately a search for a legal solution to the problem of justifying the conquest of the new territories and their expropriation.” With this novel problem in mind, Vitoria reconceptualized the existing doctrines, giving rise to the concept of modern international law based on the institution of natural law. For Vitoria “As the law of nations is dictated by natural reason, the guiding principles of international law that best serve the interest of just relations between peoples cannot be other than those of natural law.” Thus, Vitoria and las Casas brought natural law into the ambit of international law as far back as the sixteenth century. However, the classic problem of international law regarding how order is established among sovereign states was not fully addressed by Vitoria. As Anghie points out, he did not, in effect, address the question of order among sovereign states, but rather that found among societies belonging to different cultural settings. And that is also reaffirmed by Anthony Carty quoting Bartelson: “the question (addressed by Vitoria) was not how to solve a conflict between sovereigns...but how to relate concentric circles of resembling laws ranging from divine law down to natural and positive law.”

Though in his lifetime Vitoria did come to acknowledge certain rights to the aborigines, he also resorted to the premise of a just war in particular circumstances, which seemed to justify the colonial presence. Therein lies his main contradiction. Thus, as Anghie and Barreto respectively put it, Vitoria “may also be seen as an apologist for imperialism” and “is to be remembered more as a champion of the Conquest rather than as a defender of the dignity of the Indians”.


The present text is inspired by the communication presented by Paulo de Brito, Professor at the Universidade Lusófona do Porto (Faculty of Law), on 15 September 2012, in Stockholm, in the stream “International Law, Genocide and Imperialism” of the Critical Legal Conference 2012.