What explains differences in voters’ attitudes towards international trade and immigration? A growing body of research has examined survey data on voters and concluded that calculations about the impacts of trade and immigration on wages and employment prospects play a major role in determining individual policy preferences. The core claim made in these studies is that, to a large degree, voters form their views based upon material self interest. But this conclusion is puzzling for two reasons. First, few voters actually appear to know much, or care much, about trade and immigration. Trade, in particular, is a complex issue about which most survey respondents admit they have little information and to which they devote little thought. Second, separate research indicates that material self-interest rarely plays a large role in shaping voters’ opinions on other policy issues In general, and perhaps particularly for issues about which they are not well informed, voters seem to express opinions that reflect ideological principles and cultural norms, often accentuated by the specific manner in which issues are framed by political actors and by survey questions. We have addressed these issues in a series of papers.