This chapter examines the historical sweep of the policies of the United Kingdom and the Republic of Ireland in dealing with the terrorist actions of the Irish Republican Army (IRA). The author argues that the “success or failure of British counterterrorism policies has depended heavily on the state of relations between London and Dublin” and that the “eventual resolution of The Troubles in Northern Ireland hinged crucially on a close political alliance” between them. In this conflict, identity politics had a profound impact on Anglo-Irish security. For example, the British counter-insurgency strategy of the early 1970s, with its violent attacks against Catholic communities in the north, alienated the Irish state. However, when Britain switched to a policy of “criminalization, normalization, and Ulsterization,” the common values of democracy, repudiation of violence, rule of law, and a future within the European Community, made it easier for the two sides to come to a common negotiating position. In doing this, the British essentially sought to undermine the positive identity that the Provisional IRA was trying to promote among its constituents.