The British constitution has always been an imperial constitution. To deny this is a common, if mistaken, position in the civil war over its true nature. The institutional structure and ideological discourse of the British constitution always extended beyond the pale of England and the English people. For nearly a millennium the British imperial constitution has expanded and contracted across the globe to govern millions of disparate peoples as subjects of a common Crown. The Norman reconstitution of the English nation began by fusing the multiplicity of local laws into a single common law for English people. Over the seventeenth century the rise, demise and then compromise of the Crown against Parliament was played out in a long civil war fought across the Atlantic and fuelled by novel political arguments drawing on new colonial knowledge about Indigenous peoples. A second civil war in the following century saw most American colonists break free from the imperial constitution, which was then reconstituted to satisfy some remaining subjects and to suppress others. In the nineteenth century a third civil war of sorts erupted across the empire as Hindu and Muslim, Métis and Māori, and Black men and women from Jamaica to the Gold Coast rose up in armed resistance to British imperial governance. Each rebellion drew on a global discourse on the British imperial constitution that justified or rejected competing political visions of collective life.