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.

本研究报告提供了对巴西政党意识形态立场的更新和扩展点估计，以及对 1985 年重新民主化以来所有总统立场的新颖估计。总统和政党共同对巴西版联合总统制的可操作性负责。随着时间的推移，将这些关键政治行动者置于一维的左右空间中，揭示了制度矩阵面临的挑战日益增加，特别是自 2013 年以来。政党之间的意识形态极化急剧加剧，总统与国会的距离越来越远，政治中心越来越空旷。随着总统路易斯·伊纳西奥·卢拉·达席尔瓦开始他的第三个任期，联合总统主义正遭受前所未有的意识形态压力。