The Anti-democrat Diploma: How High School Education Decreases Support for the Democratic Party∗

Attending high school can alter students’ life trajectories by affecting labor market prospects and through exposure to ideas and networks. However, schooling’s influence competes with early socialization forces, and may be confounded by selection biases. Consequently, little is known about whether or how high school education shapes downstream political preferences and voting behavior. Using a generalized difference-in-differences design leveraging variation in U.S. state dropout laws across cohorts, I find that raising the school dropout age decreases Democratic partisan identification and voting later in life. Instrumental variables estimates suggest that an additional completed grade of high school decreases Democrat support by around fifteen percentage points among students induced to remain in school by higher dropout ages. High school’s effects principally operate by increasing income and support for conservative economic policies, especially at an individual’s mid-life earnings peak. In contrast, schooling does not affect conservative attitudes on non-economic issues or political engagement.