The Welfare Reform Act of 1996 generally restricted immigrants' eligibility for welfare to those who had naturalized. By increasing the salience of naturalization, the law provides a unique opportunity to examine how social and economic contexts of reception influence immigrants' pursuit of citizenship. This paper summarizes instrumental-legal (IL) and social-contextual (SC) theoretical perspectives on the foundations of citizenship and develops hypotheses on how social and economic contexts of immigrant reception after welfare reform influence naturalization behavior. Using General Social Survey (GSS) data and longitudinal data from the Survey of Program Dynamics (SPD) for 1988-2002, the research finds that hypotheses about the influence of the social context of reception, as reflected in state-level favorability of attitudes toward immigrants, are most consistently supported in the data. The results hold important implications for both theories of immigrant incorporation and ideas about what constitutes the most effective policy instruments to enhance the social and economic status of immigrants. (Contains 4 tables, 2 figures, and 1 note.)