This dissertation argues that revisions of the “Black Legend”—a set of Anglophone dogmas about Spanish tyranny and racial degeneracy—conditioned the terms for both political conflict and possibility in the nineteenth-century Americas. The project specifically attends to the ideology’s displacement from Spanish imperialism to the independence movements in Spanish America (1808 - 1826), which in turn enthralled the diplomatic imagination of the early United States. With the balance of power newly at stake in the hemisphere, Anglo-Americans relied on the Black Legend to encode the emergent polities in Spanish America with longstanding representations of the inhabitants’ political illegitimacy, sociopolitical dysfunction, and non-binary “casta” system of racial relations. I trace this language of sociopolitical taint not only in discourses of U.S. expansionism, but more importantly in instances of non-statist, transamerican political innovation. The project juxtaposes canonical, nineteenth-century U.S. literature and non-traditional texts by Spanish Americans, such as diplomatic correspondences, political tracts, subaltern rumors, and propagandist pamphlets. I assemble what I call an early Latinx counter-archive, which re-narrates Spanish America’s benighted sovereignty as an opportunity to envision forms of political community capable of disrupting Anglo-American imperial power.