Consensus democracy among the main Chilean political forces ended abruptly after the 2013 presidential and parliamentary elections, the most polarized elections since the return to democracy in 1990. Relying on spatial voting theory to uncover latent ideological dimensions from survey data between 1990 and 2014, this study finds patterns of gradual polarization starting at least ten years before the collapse of consensus, based on an increasing demobilization of the political center that misaligned politicians from their political platforms (particularly in the center-left parties). That phenomenon changed the political support for the two main political coalitions and the intracoalition bargaining power of their various factions. The pattern also helps to explain the process behind the 2015 reform of the electoral system.