After the Civil War (1861-1865), the United States faced a problem of "reconstruction" similar to that confronted by other nations at the time and familiar to the US since at least the Mexican-American War (1846-1848). The problem was one of territorial and political (re)integration: how to take territories that had only recently been operating under "foreign" governance and integrate them into an expanded nation-state on common structural terms. This paper considers the significance of education in that process of state (re)formation after the Civil War, with particular attention to its role in federal territories of the US West. Specifically, this paper analyses the role that education-based restrictions on citizenship, voting rights and office-holding played in constructing formal state power in the cases of five western territories: Hawaii, Indian Territory, Oklahoma, Arizona and New Mexico. A focus on the significance of education in these cases both advances and challenges literature on the "hidden" and decentralised structure of national policy-making in the US. It adds to that literature by illuminating how education served as an indirect tool of national policy in the West, effectively shaping the structure of power in other policy domains. At the same time, by focusing on the US West, the present analysis challenges the idea that national governance in the US was particularly "decentralised" or "hidden". It highlights instead: (1) the role of colonial racialism in shaping national responsibility and authority for education in the US; and (2) the significance of education as both an alternative and a corollary to war in establishing US colonial power.