While public opinion about foreign policy has been studied extensively in the United States, there is less systematic research of foreign policy opinions in other countries. Given that public opinion about international affairs affects who gets elected in democracies and then constrains the foreign policies available to leaders once elected, both comparative politics and international relations scholarship benefit from more systematic investigation of foreign policy attitudes outside the US. Using new data, we find a common set of core constructs structuring both American and European attitudes about foreign policy. Surveys conducted in four countries (the US, the UK, France, and Germany) provide an expanded set of foreign policy-related survey items that are analyzed using exploratory structural equation modeling (ESEM). We specifically test for measurement equivalence and find a common four-factor structure that fits the data in all four countries. Consequently, we make valid, direct comparisons of the foreign policy preferences of four world powers. In the process, our four-factor model confirms and expands previous work on the structure of foreign policy attitudes. We also demonstrate the capability of ESEM in testing the dimensionality and cross-national equivalence of social science concepts.