In political science, federalism is often treated as an “antithesis” to empire. While Canadian Politics has recently become more attentive to the importance of ongoing settler colonialism as conditioning Canadian political life writ large, this has yet to induce a paradigm shift in understanding how the institutional logics of the state were established by, and in order to advance, colonial and imperial ends. This article contributes to this broader understanding by exploring how, in Canada, the federal arrangement congeals a constitutionalized whiteness that facilitates both the internal coherence of a settler class and its subsequent continental expansion. Attentive to the importance of this constitutional development within a world-spanning imperial context, this article also suggests that the simultaneous innovation of Dominion status contoured the early twentieth-century's global colour line, as self-determination was increasingly devolved to other white settler polities. The contradictory realities of these processes are also noted.