Over the last decade, critical historiographers have established that the story of a First Debate, which tells of a struggle between idealism/utopianism and realism between the 1920s and 1940s, is a misleading characterisation of the history of academic international thought. This article adds to this critical literature by exploring how the story of a First Debate became a part of disciplinary orthodoxy between the 1950s and 1990s. Our analysis reveals that scholars produced the myth of a First Debate by detaching the concept of a struggle between idealism and realism from the unique historical milieu in which it was conceived, and employing this dichotomy for a new set of rhetorical purposes. We use these findings to suggest refinements for the historiographical methods employed to understand past international thought, and to illuminate the historical contingency of contemporary notions of scholarly purpose in international relations.