The chapter presents the setting in which the FA was born and in which it developed over the years. The combination of the exhaustion of the ISI model, increasing political polarization and the height of the Cold War dramatically determined the political dynamics of the late 1960s and 1970s and engendered a context of increasing authoritarianism and political violence. The fight against increasingly repressive governments was a significant incentive for the new party. Public opposition to the neoliberal agenda of the different governments that succeeded the authoritarian regime (1971–1985) also contributed to the FA’s increasingly successful electoral. In 2005, the FA gained office and won three consecutive national elections with an absolute majority in parliament. It was one of the most successful parties of the so-called “left turn.” During its time in government, the party enacted structural reforms in various policy areas. In terms of socioeconomic reforms, the FA approved a tax reform, a health-care reform, and was one of the two parties of the “left turn” that enacted deep labor market reforms. The FA also pursued a distinctive progressive agenda in the region that led to the legalization of abortion, same-sex marriage, and the liberalization of cannabis use.

There have been other mass-organic parties in Latin America. This chapter discusses the FA case in comparative perspective. The literature has emphasized the role of exogenous factors or the ability of party leaders to strategically “adapt” to explain the transformation of formerly mass-organic parties. The case of the FA, which confronted similar exogenous challenges, calls attention to the relevance of organizational structure in determining party activists’ level of engagement. Organizational design is crucial for fostering and reproducing activism. The chapter reviews the case of the Partido dos Trabalhadores (PT) in Brazil, a former mass-organic leftist party that turned into a professional–electoral party. The PT is the case that most closely resembles the FA in its emphasis on grassroots activism. The comparison with the PT, as a negative case, increases the theory’s analytical leverage. Second, the chapter discusses the case of the FA as a strange electoral alliance or coalition. It compares the case of the FA with other leftist coalitions in Latin America, with a special focus on the experiences of leftist coalitions in Chile, showing that the FA developed a distinctive, shared organizational structure that is not observable in other, similar electoral alliances.

This chapter describes grassroots activism and the FA’s peculiar organizational structure in which 7,000 grassroots activists have a significant autonomous voice in the FA decision-making bodies. Grassroots activists’ participation in the FA occurs in Base Committees (the movement) and in the different FA factions (the coalition), two different avenues of engagement with the FA. In the former, there is no direct control of factions, leaders, or party elites because Base Committees are not involved in candidate selection. The chapter provides a thick description of the party´s structure and shows the relevance of activism in the FA and its interaction with leaders and factions in party life.

Uruguay’s Frente Amplio (Broad Front, FA) is a mass-organic institutionalized leftist party. It is a deviant case that helps explicate the reproduction of mass-organic party organization and activism. The peculiar internal structure of the FA and the rules that ensure a role for grassroots activists in the highest decision-making bodies of the party are a product of the extraordinary conditions that existed at the time of the party’s birth in 1971. The intense autonomous activism that occurred during this stage acts as a historical cause. The decision-making authority of the grassroots activists, granted incrementally since the FA’s foundational stage, enables activists to block changes that reduce their power, engendering a lock-in effect and positive feedback. These rules grant FA activists a significant voice, which imbues activists´ participation with a strong sense of efficacy. This perceived efficacy operates as a selective incentive for activists to engage with the party. The chapter develops this theoretical argument and justifies the selection of the FA as a deviant case of party reproduction.

The final chapter concludes by summarizing the argument and identifies three major challenges for the reproduction of intense attachment. The main theoretical lesson of the FA case is that a political organization can remain vital over time and reproduce itself when the organization affords grassroots activists a potentially significant role through rules and through actors who ensure the enforcement of such rules. Nevertheless, the analysis did not aim to predict whether this organizational structure will continue to reproduce itself or whether FA grassroots activists will continue to exhibit intense levels of engagement in the future. The chapter also identifies three major challenges facing the FA. First, the FA is subject to the temptation of transforming its internal structure into a broad network of adherents who exhibit low levels of participation. This change would reduce individuals’ incentives to invest in developing the organization. Second, for Uruguay’s younger generation, the FA has always been the party in government. This creates a challenge for the FA to create a narrative that preserves its transformative vision of the future. Third, the FA faces political-economy challenges that confront any successful political organization in a developing country, especially the tension between growth and redistribution and the challenge of incorporating and politically organizing the poor and informal sectors.