Legislative cohesion in party groups in the constitutional convention in Chile, 2021–2022

This paper analyzes legislative cohesion in the Chilean Constitutional Convention (2021–2022), a one-off deliberative body composed of both party members and independents. With data from 4,669 roll call votes and applying Rice and Unity indices, we examine how party composition, member resignations and time influenced cohesion across party delegations. We find that cohesion declined over time, but initial delegations with more party members and higher resignation rates exhibited greater internal unity throughout the process. In contrast, by the end of the process, delegations with more party members were less cohesive, suggesting that independents, despite lacking formal structures, maintained stable voting blocs. These findings challenge assumptions about the disruptive role of independents and highlight the fluid nature of group dynamics in temporary legislatures. Our study contributes to the literature on legislative behavior by demonstrating how institutional design and political alignment shape cohesion in non-traditional lawmaking bodies, offering broader insights for comparative analyses of constitutional conventions.