The Choctaw Nation of Oklahoma is headquartered in southeastern Oklahoma and has a tribal citizenry of just over 175,000. The tribal government currently compacts almost all of the tribe's Bureau of Indian Affairs and Indian Health Service program funding and runs dozens of tribal businesses that today fund more than 80 percent of the tribal programs and services. Little scholarship exists about the era of its tribal history that spans the years between allotment in the early 1900s and the tribal nation-building of the 1970s, the era that is the focus of this article. Despite the dearth of scholarship about this era of Choctaw history, by the late twentieth century a dominant scholarly narrative of this period had emerged. This narrative alleges that, during the greater part of the twentieth century, many Choctaws pursued a strategy of assimilation into the larger, non-Indian society and acculturation to white culture. For many scholars, the ultimate expression of Choctaw assimilationist aspirations during these years is the tribe's response to the termination era of federal Indian policy (1945-1960). Using interviews and archival research that the author conducted in 1995-1996 and 2005, this article raises questions about the extent to which the people supported this effort to terminate the tribe and thus the extent to which assimilationist aspirations defined Choctaw experience during these years. After situating the termination crisis in broader local processes and realities, the author then turns to the primary goal of this article: documenting the anti-termination movement. She explores the origins and development of this political protest movement, the actions that its leaders and members undertook, and the ways Choctaws responded to the mobilization efforts of the movement's leadership. This resistance movement not only helped secure the repeal of the law mandating Choctaw termination but also produced a new Choctaw nationalism, a nationalism that later helped fuel the Choctaw nation-building of the 1970s and 1980s. She ends by considering the questions that her material raises about the intentions that underlay the adoption by many Choctaws of a strategy of white acculturation during this period. Her evidence suggests that this Choctaw strategy was fueled by goals other than political assimilation and that the mid-twentieth-century Choctaws saw no contradiction between pursuing white acculturation and being against political assimilation. (Contains 73 notes.)