As the article illustrates, accusations and assertions of genocide pervade both historical and contemporary readings of Irish history. Ireland thus provides an important case study of the relationship between colonialism and genocide. The paper addresses the genocidal claims made by “both sides” of the colonial nexus in Ireland: British and Irish, native and settler. It asks what wider lessons Irish history provides in terms of contemporary genocide research. It suggests that there is an elective affinity between “genocide” and “colonialism.” It also posits a specific connection between different forms of colonialism and a concomitant genocidal logic. The paper contends that the study of colonialism in genocide research also reveals a specific connectedness between the state and the logic of genocide. In terms of processes of truth and reconciliation, acceptance of this elective affinity between the colonial state and genocide is the first step towards liberation for everyone trapped in the genocidal logic at the heart of the colonial nexus.