Legality, Retroactivity, and Historical Injustices: Rethinking Criminal Responsibility for the Conquest of the Desert

This paper examines whether the violence committed against Indigenous peoples during the Argentine Conquest of the Desert (1878–1885) can be recognized as criminal without violating the principles of legality and non-retroactivity in criminal law. The study challenges a formalist interpretation of legality that limits criminal responsibility to conduct explicitly codified at the time of the events. Through a legal-philosophical methodology combining doctrinal analysis with historical sources —including legislation, parliamentary debates, constitutional principles, and contemporary press accounts— the paper argues that acts such as enslavement, rape, forced confinement, and mass killing were already recognized as wrongful within the Argentine legal order and the law of nations. Drawing on the distinction between mala in se and mala prohibita crimes, the paper defends a comprehensive interpretation of legality that rejects arbitrary distinctions between military personnel, prisoners of war, and civilians in the recognition of fundamental rights.