Four general hypotheses concerning the sources of university students' political attitudes are presented and evaluated in this paper. A cross-sectional survey of American male Harvard University graduate students was conducted with a questionnaire dealing with attitudes toward United States involvement in Vietnam. Responses were analyzed by computer and relevant statistical tests were used to verify each hypothesis. The findings contribute to the understanding of the determinants of political attitudes and to the understanding of the relationship between students' political attitudes and their general values. An appendix includes tables of data compiled in the study. (SHM)