The author argues that the increase in support for same-sex marriage in the United States must be interpreted in light of the changing social imagination of homosexuality. The author measures the social imagination at the micro level by comparing the frequencies and semantic contexts in which two cohorts use metaphors and analogies to talk about same-sex marriage. Younger informants articulate them in ways that characterize homosexuality as identity, whereas older informants characterize homosexuality as behavior. Because the former image replaced the latter as hegemonic, cohorts coming of age after 1990 tend to support same-sex marriage, and older cohorts are changing their attitudes.