After the final defeat of the Spanish forces, and the declaration of independence of Argentina and Chile, these latter abrogated the Treaty of Quillin between the Spanish Crown and the Mapuche, and declared Mapuche land as theirs by decree. Under the same pretext of promoting civilization used by the Spanish, they started a gradual take-over of Mapuche land that led to military aggression, persecution and extermination of entire communities.
In Argentina, debate raged in the 1870s as to how to solve the "Indian Problem". Two main positions crystallized. The one propounded by Minister of War, Alsina, consisted of containment, using a line of forts and ditches, and aimed at a gradual integration of the indigenous tribes. The second, propounded by his successor, General Julio A. Roca, advocated uncompromising conquest and subjugation. With the same clarity as the policy of Manifest Destiny in the United States, the likes of Roca viewed that herein lay the future of the Argentine nation.
Roca led an army south in 1879, and his brutal Conquest of the Desert was effectively over by the following year, leaving over 1300 indigenous dead and the whole of Patagonia effectively open to settlement. Roca was heralded as a hero, and swept to victory in the 1880 presidential election on the back of his success. He believed strongly in a highly centralized government and consolid ated his power base by using the vast new tracts of land as a system of patronage.