Since 2005, the Movement Toward Socialism (MAS) has become a predominant party in the Bolivian party system. Despite its origin as a small, indigenous, and peasant-based party, the MAS has achieved an electoral performance unprecedented in Bolivian political history. What accounts for its electoral rise? Unlike available explanations based on sociostructural, institutional, or contextual factors, this article argues that ideological location decisions served as a signaling device that allowed the MAS to differentiate itself from its competitors. In so doing, the party managed to transcend the border of ethnic and regional cleavages, appealing to a broader electorate, which contributed decisively to its electoral success. Using data from public opinion surveys and based on statistical models, this article shows that ideology was pivotal in Bolivians’ decisions to vote for the MAS, particularly during the early period of its electoral takeoff.
