The 21st Century Americanism survey was conducted to study (1) the multidimensional nature of American identity (“Americanism”); (2) resentment among Whites toward immigrants, Latinos, and Asians, fueled by perceptions that these groups violate the cherished norms that constitute American identity (“symbolic nativism”); (3) how perceptions of discrimination affect the process of “becoming American” among ethnic minorities (“reactive ethnicity”); and (4) the relationships among these issues and public opinion on policies that address ethnic change. The data collection began in July 2004 and was completed by October 2004.