The constitution-making process in Chile came about as result of a political agreement among political parties (traditional actors) forced by the persistent pressure from the social movements since 2006 onwards. The idea of such an agreement had been elusive in the political sphere because there was no single transversal position concerning the need to replace the Constitution nor was there agreement as to the mechanism to bring it about. The social unrest in October 18, 2019 elevated the costs of continuing to avoid the constitution-making process, even though the aspiration had been present quite some time. The social unrest caused entrenched resistance to tumble. Together with the local experiences of citizen deliberation (assemblies and self-convened cabildos), a window of opportunity emerged and the process to replace the constitution was viewed as a chance to channel the social and political crisis through institutional means. Under these circumstances, Chile provides an interesting case for studying the role of social organizations and mobilized citizenship participation, as agents of institutional change, “from below”.