Massive social unrest broke out in Peru and Chile in recent years. In both countries, the constitutional issue was central in the articulation of protests. However, elite reactions to these movements were different. In Chile, political institutions sought to accommodate the popular demands, launching a process of constitutional reform that attempted to appease discontent redirecting it to institutional politics. Whereas in Peru, the political elite was unable to agree on a process of constitutional revision. The “estallido social” of 2020, which led to the ousting of President Merino, re-emerged two years later with more intensity in the aftermath of the failed coup d’état attempted by President Castillo. To understand these different responses to mass social unrest, this article proposes a theoretical framework grounded in historical institutionalism. The main argument is that authoritarian regimes are critical junctures that produce enduring legacies in the power configurations of the polity. Legacies will vary depending on two aspects: whether authoritarianism consolidates a power basis, and how these regimes end. Different socio-political legacies favored distinct elite reactions and approaches to the threats posed by popular movements. To illustrate this argument, the article draws on previous studies and provides preliminary evidence. Overall, the article contributes to political sociology by integrating critical junctures and outcomes of social movements literature