In a national referendum held on October 5, 1988, Chileans soundly defeated General Augusto Pinochet''s bid to extend military rule for another eight years. Voters chose instead to reestablish democratic rule. This event marked a crucial turning point after the 1973 coup that had put an end to four decades of uninterrupted democracy. One of the military''s primary objectives was to overhaul the country''s chaotic party system, identified as a prime example of extreme and polarized pluralism by the renowned scholar Giovanni Sartori. The authoritarian rulers blamed political parties for the political and economic instability that had plagued Chile in the preceding years and, after assuming power, banned political parties and persecuted many of their leaders. In the subsequent years, the military altered political institutions and established a new electoral system in an attempt to reconfigure partisan politics upon relinquishing control. The post-authoritarian party system was indeed different from its predecessor, but not in the way military rulers had anticipated. The transformation, which began during the years of military rule, gave way to a fundamentally different configuration of inter-party competition, evident in new patterns of government formation, electoral dynamics, and legislative conflict.

In this book, I argue that this transformation amounted to a realignment of the party system, marked by a new political divide and initiated by two critical elections: one in 1988 regarding the continuation of military rule and another in 1989 to elect a new president and members of Congress. Unlike its predecessors, the post-authoritarian party system proved to be remarkably stable. The stability of the post-authoritarian system, this book will show, was not only the result of the new political divide that began to structure competition as the military was beginning its retreat but also the consequence of a new institutional framework designed by the outgoing rulers. During the two decades following the return to democracy, Chile was hailed as a beacon of stability, institutional strength, and consensual politics in a region beset by volatility and conflict. Among experts in the field, Chile was often described as having a highly institutionalized party system (Coppedge 1998, Mainwaring 2018, Mainwaring and Scully 1995, Payne et al. 2003, Stein et al. 2006). Then, to the surprise of many, the post-authoritarian party system broke down.

The unraveling occurred rather rapidly, starting in late 2017 with national elections. A significantly more fragmented and polarized party system came into place. In addition, the long-lasting alliance between leftist parties and Christian Democrats, which had initially formed during their joint pursuit of democratic elections and solidified during subsequent government coalitions, dissolved. Moreover, by the end of 2021, for the first time since the return to democracy, neither contender in the second round of the presidential election belonged to one of the two coalitions that had dominated electoral competition during the previous three decades. In March of 2022, Gabriel Boric, a radical outsider who built his career opposing the traditional parties, assumed the presidency while leading a new leftist coalition. The post-authoritarian party system did not end with a realignment, as it had begun. There was neither a high turnout critical election nor the emergence of a new cleavage. Instead, I argue, its demise was precipitated by an electoral reform that replaced the existing rule with a higher-magnitude proportional representation system.

Other gradual processes contributed to a context conducive to change, including the erosion of linkages between parties and voters and the diminishing relevance of the regime cleavage, which had been significant in the first two decades after the transition to democracy. However, the catalyst for change was the electoral reform, with the primary casualties being its architects. Throughout this book, I aim to provide a comprehensive analysis of stability and change in Chile''s party system. Through descriptive inference, statistical analyses, and a variety of original data, I seek to explain the origin and death of the post-authoritarian system and the in-between decades of stability. This analysis begins with the democratic era preceding the 1973 coup and extends to the aftermath of the 2021 elections. My account of party system change following military rule expands previous work on this subject and challenges early interpretations from renowned scholars of Latin American politics who, instead of profound transformations, emphasized continuities in fragmentation, competitive dynamics, and class conflict. Rooted in institutional analysis, my arguments about stability and the eventual demise of the post-authoritarian party system provide an alternative account to those focusing primarily on the sociological aspects of this period or solely on electoral evidence. (Excerpted from the Introduction).