Scholars have made little progress in exploring the degree to which research on belief structures among Americans may be generalizable to other political systems and geopolitical contexts. The distribution and structure of mass beliefs related to nuclear security, missile defenses, and nuclear energy issues in the United States and Great Britain are analyzed using data from telephone surveys simultaneously administered in both countries. In foreign and domestic areas, the British and American belief systems vary chiefly in the central tendencies of the beliefs held but not in the structural relationships among those beliefs. Findings provide evidence for a hierarchical model of policy beliefs with differential adjustments based on situational conditions, but also raise questions about the kinds of conditions--geopolitical and institutional--that give rise to these similarities. (Contains 4 tables, 2 figures, and 8 footnotes.)