American Studies is an academic discipline whose object of study is the United States of America and everything associated with it, and American sociologists largely ignore it. American Studies largely ignores American sociology. What causes this mutual exclusion? An outline of the disciplinary history of American Studies and journal article citation data show that the relationship between sociology and American Studies is weak and asymmetrical; American Studies cites sociology more often, but very little and not by much. I argue that mutual exclusion is due to mutual distrust in methods: sociology sees itself as a science, while American Studies, with roots in history and literature, does not. This article serves as a case study in the limits of interdisciplinarity.