The Sino-American relationship is arguably the most important bilateral relationship in the world. Whether this relationship remains peaceful or becomes conflictual will have far-reaching economic and political ramifications. For more than two decades, American analysts have been attempting to answer one question: Is China a threat to the United States? The result has been a voluminous collection of data that equally supports contradictory answers. I contend that if we want to understand the probable course of the Sino-American relationship, we need to ask a different question: When and why are Americans likely to perceive China as a threat? This paper reports the results of a social psychological experiment designed to explore the basis of American attitudes toward other states in general and toward China specifically. Contrary to expectations that economic insecurity drives American attitudes toward economic competitors, this study finds that American attitudes toward China are shaped primarily by cultural and institutional judgments. These results contribute to the field of IR by challenging preconceptions about the extent and potential impact of Americans' economic insecurities, by contributing to a nascent constructivist literature that examines how threat is constructed in the national imagination, and by informing how policymakers approach important bilateral relationships.