Trajectories of defense cooperation: ZOPACAS and the South American Defense Council

Abstract

This article compares the trajectories of two defense cooperation mechanisms born under the premise of regional strategic autonomy: the South Atlantic Peace and Cooperation Zone (ZOPACAS), created in 1986, and the South American Defense Council (SADC), created in 2008 within the framework of the Union of South American Nations (UNASUR). Between 2018 and 2026, the two mechanisms followed opposite paths, as ZOPACAS was revitalized after a decade of inactivity, culminating in the IX Rio de Janeiro Ministerial Meeting (2026), while the SADC lost political relevance after the withdrawal of most of its founding members from UNASUR. The objective is to identify the institutional and political-geographic factors that explain this divergence. A most-similar-systems case study methodology was adopted, based on a literature review and documentary survey. The degree of formal institutionalization, the degree of exposure to domestic political-ideological ruptures, and the degree of extraregional alignment of member states explain a significant part of the divergence: lightweight mechanisms with low sovereign commitment, such as ZOPACAS, prove more resilient to changes in government, while densely institutionalized mechanisms, such as the SADC, become more vulnerable when the political alignment sustaining them dissolves. It is concluded that this resilience comes at a cost: the same institutional lightness that allows ZOPACAS to survive long periods of inactivity limits its capacity to produce substantive commitments in technically demanding areas, revealing a structural limit of the strategic autonomy project in the Global South.