The relative influence of stages of political socialization on the adult political orientation and activities of former American and Japanese student activists is examined. A causal model of the stages of political socialization, including family and school, student activism, and adult roles, is compared with the political fate of student activists who participated in the 1960 antisecurity treaty movement in Japan and the civil rights movement in the American South. The results indicate that student activism in college is the best predictor of adult politics in both countries. Family and early school political socialization are only weak predictors of future adult politics. Adult political socialization can be either a facilitator or a constraint for maintaining political commitments. In the United States, career choice has no direct effect because student activism strongly affects career choice. In Japan, career choice has a strong effect on adult politics. Former Japanese students in the knowledge and human services industries have greater left-wing commitments. For American student activists, remaining free of family affiliations is a facilitator for left-wing politics; while in Japan, family obligations are a facilitator of left-wing politics. (Author/DE)