It Happens Gradually, then Suddenly: Multiparty Coalitions and Deinstitutionalisation of Mexico’s Party System

Does the appearance and entrenchment of multiparty coalitions contribute to deinstitutionalisation of the party system, and with it of democracy? The aftermath of the 2018 Mexican federal election has put into question the robustness of Mexico’s party system with existing research assessing it as highly institutionalised. Using federal and state-level electoral and survey data from 1993 to 2018, as well as empirical analyses, this paper shows how the emergence of coalitions in the electoral system, gradually but constantly, eroded the party system which before the 2018 election had ceased to be institutionally robust. In particular, coalitions had an effect in party competition with the formation of heterogenous alliances, increased party abandonment, lower party identification and party roots, and increased policy fluidity. The evidence contributes to a growing literature on the drivers and effects of party system collapse in presidential systems and democratic backsliding. With the 2018 victory of Andres Manuel Lopez Obrador, Mexico, like other democracies around the world, is facing challenges to its democracy and its institutions. Academics consider and have undermarked the Mexican party system as strongly institutionalised, both for Latin American standards as well as in comparison with other democracies around the world. Some, even consider that despite its contemporary challenges the Mexican party system will remain highly institutionalised. Largely, this view is rooted in the patterns of competition and programmatic differences that arose between the three largest parties across the 1990s, when electoral competition took momentum. However, recent electoral results are puzzling if we take for granted the view that the Mexican party system was strongly institutionalised. Since the 1990s the Mexican party system has evolved from a system with three differentiable and defined competitors, to a multiparty system where heterogenous coalition-making has become the norm and the main form of political contestation. Using federal and state-level electoral and survey data, as well as empirical analyses, this paper shows that the emergence of coalitions gradually eroded the party system in Mexico, which before the 2018 election had ceased to be institutionally robust. The paper proceeds as follows. Section one will show the negative effect that coalition making had in the stability of competition in the Mexican party system. The second section shows how parties deinstitutionalised as coalitions became entrenched. Afterwards, I discuss how coalitions affected policy stability by looking at the changes in budgetary allocations. Lastly, I will offer conclusions and implications of the findings.