Multiculturalism has emerged to challenge liberalism as an ideological solution in coping with ethnic diversity in the United States. This article develops a definition of political multiculturalism which refers to conceptions of identity, community and public policy. It then analyses the 1994 General Social Survey and a 1994 survey of Los Angeles County to assess the contours of mass support and opposition to multiculturalism, testing hypotheses concerning the role of social background, liberalism-conservatism and racial hostility. The main conclusions are that 'hard' versions of multiculturalism are rejected in all ethnic groups, that a liberal political self-identification boosts support for multiculturalism, and that racial hostility is a consistent source of antagonism to the new ethnic agenda of multiculturalism. There is strong similarity in the results in both the national and Los Angeles samples.