This chapter addresses the ambivalent relation of Irish Protestantism to settler identity in the post-1922 period. In the Republic, Irish Protestants accommodated to the new state and majority Catholic government; in Northern Ireland, “a Protestant state for a Protestant people” took on the forms of a settler-colonial state. Protestant supremacy expressed itself in triumphalist cultural forms and in legalized and informal discrimination against Catholics. Northern Ireland offers a “laboratory” for the formations of the settler colony that clarifies the tendencies of settler-colonial entities: the necessary supremacism or racism, the sectarianization of working-class allegiances, the disproportionately violent response of the state to the demand for rights, and the necessity for the withdrawal of “mother country” support for a peace process to begin. Northern Ireland highlights how settler mentalities are the effect of a structure of dominance, not an unchangeable given. Analogies with Palestine/Israel are frequently invoked and the Northern Irish peace process might suggest a just way to end Israel’s colonization of Palestine. Northern Ireland indicates that the entrenched structures of racial or ethnic supremacy in settler-colonial societies are not necessarily permanent or endemic, but capable of transformation if relations of domination are dismantled.