This essay documents growing partisan social uprootedness across Latin America over time, manifested in diminishing social trust toward parties, debilitation of links between parties and social collectivities, lowering levels of partisanship, and rising incidence of personalism in the electorate. It focuses on some unrecognized and undertheorized causal factors behind partisan involution in the region, putting emphasis on mutually reinforcing processes. First, it identifies forces endogenous to the traits of origin of diminished parties that foster their uprootedness and decay; second, it lays out some of the manifold ways that the weakening of political parties fuels regime malperformance, in a mutually reinforcing vicious circle; third, it outlines the existence of mutual feedback loops between political agency and structure; fourth, it identifies various agential sources of party decay. There are strong theoretical and empirical reasons to expect continued party deinstitutionalization across Latin America going forward.

This research note contributes updated and extended point estimates of the ideological positions of Brazilian political parties and novel estimates of the positions of all presidents since redemocratization in 1985. Presidents and parties are jointly responsible for the operability of Brazil’s version of coalitional presidentialism. Locating these key political actors in a unidimensional left–right space over time reveals rising challenges to the institutional matrix, particularly since 2013. Ideological polarization among parties has sharply increased, presidents have become more distant from Congress, and the political center has become increasingly vacated. Coalitional presidentialism is being subjected to unprecedented ideological stress as President Luiz Inácio Lula da Silva begins his third term in office.