The Caste War that devastated Yucatán in the middle of the nineteenth century cast a long shadow across ethnic relations and politics in the state decades after its effective end. During the Mexican Revolution and the subsequent period of national reconstruction, revolutionary politicians invoked the Caste War as a precursor to the Revolution and as justification for post-Revolutionary projects, in particular indigenismo. The state’s indigenist policy advocated, in the words of Alan Knight, the “emancipation and integration of Mexico’s exploited Indian groups.” To this end, it offered indigenous people education, legal support, even land; however, these “modernizing” policies also destroyed or appropriated much of their culture and subordinated them to the state. The legacy of the Caste War shaped such indigenist projects in Yucatán from the Revolution to (at least) the 1930s, but its influence was strongest during Cardenas’ visit to Yucatán in August of 1937. The president not only reinterpreted the Caste War to justify land reform and a broad indigenist project; he attempted to mobilize the Yucatecan peasantry along class and ethnic lines and threatened recalcitrant landlords with another caste war should they oppose him. Once armed, however, peasant soldiers turned their rifles not against the landowners but against each other. This essays explores how the Caste War’s legacy shaped the development and deployment of indigenist projects in Yucatán from the Revolution to the late 1930s, focusing on Cárdenas’ aborted mobilization. Along the way, it will consider the impact and efficacy of state-sponsored indigenismo. Above all, it seeks to understand why state efforts to champion the cause of the Maya failed to unify the rural poor of Yucatán under the banner of Cardenismo.