Intra-party Dynamics and Sub-National Influences in the Emergence of Party Splits in Brazil

Party splits are one of the main sources of change within party systems. They occur when politicians, previously affiliated with another party, leave it and create a new party organisation. While several recent studies have focused on this topic, there remains a wealth of unexplored terrain about which conditions at the intra-party level can favour or hinder the emergence of party splits. This paper aims to investigate the emergence of party splits in Brazil, focusing on the role of intra-party competition in electoral contests for both federal and state legislatures. By analysing party-level data from Brazilian states between 1982 and 2022, this study demonstrates that the overall number of candidates competing within a party, particularly viable candidates with strong electoral prospects, increases the likelihood of party splits. The paper suggests that intra-party competition may be related to party splits by exacerbating dissatisfaction among political elites and/or exposing coordination challenges within the party.