With the rise of electoral competition in Mexico, the country's state legislatures have gained greater legal and political relevance. Drawing from theories of legislative organization originally developed to explain the U.S. Congress, this project contributes to the comparative study of legislative institutions by providing the first large-scale analysis of Mexico's emerging assemblies. It adopts both qualitative (e.g., elite interviews, procedural details, etc.) and quantitative (e.g., multi-level modeling, Bayesian estimation of legislative preferences, etc.) approaches to explore the rules guiding legislative processes and study their impact. The goal is to not only improve scholarly understanding of Mexico's evolving democracy but also demonstrate the generalizability of established political theory.