As they were forcibly relocated to Indian Territory in the 1830s, the southeastern “civilized” nations, that had developed what I contend to be a form of strategic mimesis to resist colonization, seem to have become central agents on a new native-to-native middle ground based on interactions with the Osages and the Comanches. While southeastern Indian leaders had to abandon the nationalist aim they had contemplated in the East, they reproduced a state-making institutional apparatus in the West, modeled after other federal states. In appropriating the lands allocated by the government, they turned the Indian Territory into an economic, political, and cultural extension of the American republic. In the process, they became, despite them, colonizers of the Native populations of the region, who were the original owners of the lands they settled. The pursuance of a strategy of resistance through acculturation put these emigrated nations in an ambivalent position. As they reinvented new forms of sovereignty in the bosom of Federal authority, they developed a “civilizing” diplomacy oriented towards the Plains Indians that must have us reflect on the active part those Indian populations took in American expansion in the middle of the 19th century.