This paper examines ideas about democratic legitimacy and sovereignty within Ulster unionist political thought during the revolutionary period in Ireland (c. 1912–22). Confronted by Irish nationalists who claimed that Home Rule (and later, independence) enjoyed the support of the majority of people in Ireland, Ulster unionists deployed their own democratic idioms to rebuff such arguments. In asserting unionism's majority status, first, across the United Kingdom and, second, within the province of Ulster, unionists mined the language of democracy to legitimise their militant stand against Home Rule. The paper also probes the unionist conception of sovereignty by examining the establishment of the Provisional Government of Ulster in 1913, which was styled as a ‘trustee’ for the British constitution in Ireland after the coming of Home Rule. The imperial, economic and religious arguments articulated by unionists against Home Rule are well known, but the space given to constitutional rights and democratic legitimacy in the political language of unionism remain obscure. While the antagonisms at the heart of the revolutionary period in Ireland assumed the form of identity politics and sectarianism, the deployment of normative democratic language by unionists reveals that clashing ideals of representative government underpinned the conflict.