This article addresses the question of how difference has been dealt with by the social studies curriculum since its formal inauguration as part of American schooling in the early twentieth century. Over the last hundred years, cultural and ideological differences have played a large role in defining how Americans interpret citizenship education, the hallmark of social studies, and in informing notions of what is educationally worthwhile as related to citizenship. Ideological difference has, of course, been a recurring theme in textbook censorship battles and curriculum disputes over the course of this history.