After the legitimacy crisis opened by Ferdinand VII’s capture war raged for more than half a century over the vast territory of Rio de la Plata. During this period, the local people placed war at the very center of social life, which lead to alarming levels of military mobilization and eventually the terminal collapse of the central State. This dissertation raises questions about the social conditions of this total and protracted state of war. It first analyzes the transformation of social values, behavioral patterns, and institutional forms. Then it recreates the military practices that sustained the war effort for decades via massively coercive recruiting systems, guerrilla tactics and a combat order that mimicked the rural population’s way of life. Proper identification of the social mechanics that characterize this newly established “warrior society” proves a crucial fact: its constitutive elements were as much a consequence as a cause of the state of war.