Throughout history, states have sought to reshape the culture and identities of their citizens through assimilation policies and indoctrination efforts. In this paper, I show that coercive assimilation policy can cause substantial cultural change among ethnic minorities, but that these effects do not necessarily persist into later generations, and may even reverse. I focus on a historical policy in the United States under which authorities removed Native American children to distant boarding schools. I exploit the staggered recruitment patterns of schools and variation in cohort exposure to facilitate causal identification. I show that exposure to boarding schools offered few economic benefits, but did lead to rapid cultural assimilation. Treated cohorts were more likely to speak English, more likely to give their children western names, and more likely to be counted as `White’ in later censuses. However, I find that these effects reversed in the next generation, with the adult children of treated cohorts being more likely to live in a rural area and less likely to intermarry. I argue that stronger ethnic identification, associated with exposure to boarding schools and transmitted across generations, is a plausible channel for these effects. Ultimately, the schools seem to have strengthened the identities they sought to erase.