Partisan and Nonpartisan Models of Constitution-Making: A Comparative Case Study of Brazil and Chile

This paper compares Brazil's (1987–1988) National Constituent Assembly and Chile's (2021–2022) Constitutional Convention to examine how partisanship and institutional design shape constitution-making outcomes. Brazil's party-based assembly, despite internal ideological heterogeneity, achieved an accepted constitution through structured negotiation and leadership mechanisms. Meanwhile, Chile's nonpartisan convention faced fragmentation among independent constituents, had limited coordination tools, and ultimately produced a draft rejected by referendum. Drawing on qualitative comparative case approach, roll-call analysis, and matching techniques, we show that partisan infrastructure can mitigate negotiation challenges by fostering compromise. In contrast, nonpartisan assemblies may enhance inclusiveness but risk fragmentation and instability without robust coordination mechanisms that bridge internal divisions. These findings challenge the presumed superiority of nonpartisan conventions, demonstrating the importance of party-based institutional frameworks for managing collective action problems in constitution-making. In doing so, this study highlights the tension between inclusiveness and the organisational capacity required to achieve compromise-based agreements and lasting constitutional outcomes.