In the 1800s and early 1900s, the United States assigned Indian Agents--non-Native employees of the federal government--to coordinate intergovernmental efforts, to encourage the assimilation of Native peoples into European-American society, and to serve as advocates for individual tribes. Although Indian Agents no longer exist in an official capacity in the United States, the potentially contradictory expectations that informed their work continue to influence communities across the country. Instead of decolonizing education, today's curricular agents typically misrepresent the historical and future agency of Native peoples while reinforcing the patronizing, normative, dominant-culture narrative. This article outlines the critical discourse analysis of five widely adopted U.S. history textbooks, as situated within the broader scope of textbook research and emerging educational movements. Findings show that textbook authors and other curricular agents use strategies of exclusion and passivation to control the historical and curricular agency of Indigenous peoples. Given the influence of educational reform efforts such as those related to the Common Core Standards, now is the critical time to retheorize curriculum design and inquiry as dialogic, dynamic, transformational, and agentive processes. The project's conclusions demonstrate the need to confront the biases of curricular agents in order to guide the decolonization of curriculum materials.