The idea of American exceptionalism has lived a vibrant life in American political discourse, yet little research has focused on the effects that these messages have on U.S. public opinion. To bridge this gap, the present study examines the psychological dynamics that shape how Americans respond to messages that champion the idea of American exceptionalism. Specifically, I draw on scholarship on American exceptionalism in political discourse and on social identity to conduct a message experiment on a nationally sampled population of U.S. adults. The experiment examined the differential impacts of American exceptionalism messages on (a) people's own sense of American exceptionalism, (b) their sense that other countries are inferior by comparison, (c) their attitudes about whether the United States should be exempt from international laws and institutions, and (d) their attitudes about whether the United States should seek to spread its influence and values in the world.