In the 1980s, when the Cold War was raging with renewed force, social movements concerned about the prospect of nuclear war emerged on both sides of the Atlantic. They shared roughly the same objective, that is to bring an end to the nuclear arms race, but approached the challenge in different ways. One movement, the US Nuclear weapons Freeze Campaign, came to the conclusion, given lessons from the Vietnam War protests, that achieving its objectives required moderation in behaviour and message. Rather than dressing like hippies, they would dress in suits, appeal to Middle America. and mobilize citizens to pressure their congressmen (sic). Their proposals were formulated in a measured way that would minimize alienating people and appeal to the wider spectrum. In another political context, across the water, critique was somewhat more hard hitting and diverse. her than calling on the USA and Soviet Union to simply stop the development, testing, and deployment of nuclear weapons, protesters demanded actual disarmament and in some cases unilateral disarmament. While loose cooperation existed at the European level, in the form of European Nuclear Disarmament, movements in the Netherlands, Germany, or Italy had a distinctive character These critical movements shared the aim of changing the nuclear status quo, and each was shaped by the politics of its respective location, as well as the larger context of the Cold War I start with this example from the political world for two reasons. First, against this background that is the mid- to late 1980s, questions began to be raised about the theories and scientific methods of IR and the extent to which they were implicated in the production of international power (see Cox 1981; Ashley 1981, 1984; Walker 1987). Challenges to the assumptions under pinning the study of IR emerged against the backdrop of a historical context where political actors were challenging the assumptions of the Cold War. As the end of the Cold War was ushered in, further questions about these changes and the social construction of IR were for mulated. The failure of IR scholars to predict or initially explain the end of the Cold War, on the basis of the dominant theories of IR, reinforced the importance of these questions. Second, the two social movements are a useful metaphor for thinking about the construction of constructivism within IR. Constructivists, broadly defined, have shared a critique of the static material assumptions of traditional IR theory. They have emphasized the social dimensions of international relations and the possibility of change. They have, however, differed in their approach. Some have been more conscious of their broader audience and have shaped their critique in that would open a space for dialogue with mainstream scholars. Others have been more hard hitting in stating the problem and more far reaching in their critique. The two together have shaped the place of constructivism in IR. The main point-and, I might add, a very constructivist point-is that academic debate, no less than political, emerges in historically and culturally specific circumstances. This is evident in other debates that have shaped IR theory. The debate between realism and idealism was a reflection on the weaknesses of idealism after the First World War against the background of Hitler's expansion across Europe (see Carr 1946). Attempts to solidify the scientific status of realist IR were led by European émigrés to the USA, following the Second World War. The debate between behaviouralists and traditionalists pitted scholars in the USA, who wanted to make IR into a science, against the international society theorists of the English school (see Knorr and Rosenau 1969). The postpositivist debate in the late 1980s was a reaction against the dominant place of scientific method in the American context (see Lapid 1989). The dialogue over constructivism was a reaction to the third debate, or, as some prefer to call it the fourth debate (see Chapter 1), and an attempt to speak across the barricades it had constructed, while addressing problems raised by the end of the Cold War. The following develops various dimensions of the 'constructivist turn' (Checkel 1998) in IR. It begins with a general discussion of what it means to say that reality is socially constructed and then proceeds to a more in-depth discussion of related debates.