Polarization has been always identified as a problem for Latin American democracies. Yet its determinants remain largely undertheorized and without systematic evidence. This paper tackles this shortcoming with a new explanation where polarization is conceptualized as a mobilizational tool used by parties to deliver unequivocal signals to voters about their location in the policy space. The explanation holds that Parties’ strategies depend on the electoral context in which they compete, making volatility a crucial indicator of their behavior. Low-volatility contexts inhibit parties from seeking polarization due to potential electoral punishments by voters and the internal costs of programmatic change within the party organization. High volatility, however, increases the risk of electoral survival, decreasing the costs of seeking polarization. Here, volatility makes polarization more likely. Using time-series cross-sectional regression analysis for eighteen Latin American countries for 1995–2010, this paper provides robust statistical results to support the causal link between electoral volatility and polarization.