The election of December 1918 signalled an unprecedented shift in Irish political opinion in more populist and radical directions. This chapter looks at the effects of First World War on Ireland, both politically and economically, with particular focus on the Easter Rising, conscription crisis and failed attempts to achieve a workable all-Irish settlement in the Irish Convention convened in 1917. The 1918 election is explored in detail, as is the increasing utopianism and hyperbole of its more radical participants. The implications of the result for Irish unity are also examined, with particular focus given to the assumptions and contradictions that underlay Sinn Féin’s Ulster policy. It ends by looking at the lessons taken from the result and the overriding assumption that Ireland was now home to an innate and insoluble sectarian divide.