Under what conditions do South American states create regional institutions that consolidate or undermine the liberal international order (LIO)? To address this question, we compare two cases of contestation of the LIO through counter-institutionalization in the domains of migration and election monitoring, both of which are closely related to the LIO’s core political principles. We argue that the variation in the effects of counter-institutionalization—LIO-consolidating in the case of migration and LIO-undermining in the case of election monitoring—results from the interaction of two explanatory factors: the source of dissatisfaction with the LIO’s norms and institutions in a specific domain, and the preferences of the state that exercises regional leadership in support of counter-institutionalization. The article sheds light on the coexistence of liberal and illiberal tendencies in South America’s regionalism and contributes to the debate on the determinants and effects of contestations of the LIO in the Global South.
