The paper analyses the origins, institutionalization, and change of the ideas and interests that underpinned the articulation of a South American regional cooperation platform between 2000 and 2008, focusing on the interplay of ideational and material regional leadership, state interests, and external incentives, which are considered the drivers of the cooperation process that resulted in the creation of UNASUR.
Borrowing cross-paradigmatically from institutionalism, intergovernmental liberalism, and constructivism, the article explores the role of and conflict between Brazil and Venezuela’s ideas and diplomatic power in assembling regional coalitions of interests to steer cooperation in issue-areas like infrastructure and energy integration and collective security. The interplay of the variables is inserted into an analytical framework based on cycles of politicization, institutionalization, re-politicization, and institutional change, which sheds light on the role of ideas, power, and agency in promoting regional cooperation in absence of sovereignty pooling and high economic interdependence.