James F. Evans Collection, Using data obtained from National Opinion Research Center's General Social Surveys (1973-1990), this paper tests two hypotheses concerning possible changes in the sociopolitical correlates of environmental concern. The "broadening base" hypothesis predicts that environmental concern will diffuse throughout the populace, while the "economic contingency" hypothesis predicts that the economically deprived will disproportionally withdraw support for environmental protection during poor economic conditions. analysis of the data over the 18 years, however, failed to lend any clear support for either of the hypotheses. In marked contrast, results indicate that the social bases of environmental concern-at least as measured by the NORC environmental spending item-have remained remarkably stable over nearly two decades despite fluctuating economic, political, and environmental conditions. Younger adults, the well-educated, political liberals, Democrats, those raised and currently living in urban areas, and those employed outside of primary industries were found to be consistently more supportive of environmental protection than were their respective counterparts. (original)