Abstract: Few American law classes actually teach the Insular Cases. This Essay argues that this is due to a profound lacuna in mainstream constitutional study—the failure to adequately confront the extent to which the United States from its founding has been a project of empire. In part, for this reason, the field tends to have little to say about perhaps the key defining legal-political development of the American twentieth century: the country’s rise from regional player to the world’s dominant power. In exploring these omissions, the Essay highlights the place of the Insular Cases as a central ideological and institutional hinge between two modes of American imperial authority: settler conquest and global primacy. The Essay then reflects on what it would mean to take seriously the continuing role of colonialism in constitutional life as well as what lessons should be drawn for the study of constitutional law.