There has been renewed global interest in the role that schools can play to strengthen democracy, peace, and tolerance. However, empirical studies find mixed (positive, negative, and null) effects of additional years of schooling on democratic attitudes and political participation. It is unclear what explains the variation in findings. We hypothesize that individual political attitudes and behaviors are shaped, among other things, by the content of education. To test this hypothesis, we study the consequences of national primary school curriculum reforms in Mexico from 1960 to the present. Our research design combines automated text analysis of the entire corpus of textbooks used in Mexican primary schools from 1960 to the present, with difference-in-differences estimates of the impact of textbook reforms on long-run political attitudes and behaviors. The preliminary analysis suggests that the content of textbooks that adults were exposed to during primary school indeed shapes their contemporary political attitudes and behaviors. Our study helps refine our understanding of the mechanisms and conditions under which education promotes democracy.