We explain the electoral deterioration of the Chilean Christian Democratic Party (PDC, by its acronym in Spanish), which fell from 26% of the votes in the inaugural elections of democ-racy in 1989, to 4.2% in the legislative elections of 2021. We suggest three explanatory factors. First, the PDC's electoral base has always been predominantly Catholic; since the mid-2000s, right-wing parties have competed with the PDC in this core constituency partially successfully. Second, the PDC has been a centrist party, but since the late 1990s, it has faced competition from left-wing parties for these voters. Third, the internal factions of the PDC went from a co-operative dynamic to a disruptive dynamic, with accelerated changes of leadership and militant flight. All these anticipated poor results for the 2017 and 2021 presidential elections, with 5.9% and 11.6%, respectively.