124 Law and Morality Abroad (to ca. ad 1550)
to submit voluntarily to their new masters. Only if voluntary submission
was refused could conquest by armed force proceed.
López’s position was incorporated, in 1573, into a new legal ordinance
regulating the conquest pro cess. Henceforth, the word “conquest” was to
be eschewed altogether, in favor of “pacifi cation.” In dealings with Indian
groups, the positive benefi ts of Spanish rule were to be stressed. But it was
also provided that, if the natives were to oppose Spanish settlement and the
preaching of the Christian faith, then force could be used against them.
Th e Humanitarian Th esis
Another possible root of Spanish title was based on what could be called the
humanitarian thesis, the essence of which was that rulers who committed
systematic violations of natural law in the course of governing could be de-
posed by foreign parties. Its roots lie in the claim asserted by Innocent IV of
jurisdiction of the papacy to punish violations of natural law, even if they
were committed by non- Christians. Pagan princes accordingly risked such
papal intervention if they engaged in or tolerated perverted practices such as
polygamy or the worship of idols.
Applying this reasoning to the situation in the Americas, the contention
was that the native Indian rulers were guilty of various unlawful acts, in the
form of cruelty and oppression infl icted onto their subjects— and that the
Spanish were thereby entitled to wage a just war to put a stop to that wrong-
doing, even though they were not themselves the victims of it. Th is marks
the fi rst appearance in international legal history of what would later be called
the principle of humanitarian intervention. It was as controversial at its in-
ception as it remains today. Vitoria gave it at least some support, conceding
that it was lawful for the Spanish to wage war against Indian rulers who in-
fl icted “oppression and wrong” on their subjects.
Th e humanitarian argument, in a decidedly generous form, was asserted
most forcefully by the Spanish vice- regal government of Peru. Since there
was doubt as to whether the requerimiento had been read out at the time of
Pizarro’s conquest, it appears that there was greater question than in other
areas as to the validity of Spain’s legal title. Th e fi rst Spanish viceroy, Fran-
cisco de Toledo, resolved to settle the matter. He did so, largely on the thesis
that the Inca rule which preceded the Spanish one had been exceptionally