Religious Competition and the Rise of Leftist Parties: Why the Catholic Church Provided the Mass Base for the Workerss Party in Brazil

Abstract

The rise of mass-based leftist parties in developing countries poses a fundamental question: who builds leftist parties where workers are organizationally weak? Focusing on the Workers’ Party (PT) in Brazil, we argue that the spread of religious competition in Brazil’s most impoverished regions led Catholic clergy to develop extensive grassroots organizations to prevent mass defection. The lay members of these networks became candidates, party activists, and core voters, enabling the transformation of the PT into a national organization. We present statistical evidence showing that religious competition predicts the PT’s local presence and electoral support, 1982–2010. Drawing on bishops’ life histories we show that competition drove Catholics to build grassroots movements and based on survey evidence we show that these movements’ members overwhelmingly mobilized and voted for the PT. Our findings question the claim that leftist-party development is a secular process and that religious networks can only create conservative movements.