Since the end of the Cold War observers have noted that the United States and Europe have slowly drifted apart. While a number of issues have divided the close allies - from trade to environmental concerns - of particular interest is the changing calculus of transatlantic security cooperation. Realists predicted the demise of transatlantic security cooperation, constructivists and institutions theorized that it would carry on. While initially it seemed that the latter were correct, since the late 1990s realist predications would seem to be born out. Closer observation, however, reveals that while the US and Europe are not seeing eye-to-eye, the North Atlantic area is not returning to balance of power politics either. This thesis hypothesizes that the best explanation for the rift in transatlantic relations is embodied in the sociological theory of the Risk Society. As the West moves from modernity to late modernity, societies become increasingly obsessed with risks. At the international level this obsession is evident as well. During the 1990s, NATO classified its greatest 'threat' as "security challenges and risks." This dissertation reviews the literature on the transatlantic community to identify the weak points in current explanations of the conflict. It draws upon the most cutting edge work in IR related to the Risk Society thesis and uses this literature as the basis to further develop the concept of risk and a new model of security cooperation in the Risk Society. The second half of the thesis examines three cases of Western military intervention - Kosovo, Afghanistan and Iraq - to assess if the West acted in accord with a security paradigm articulated upon risk and, if so, what are the implications for transatlantic security cooperation.

La sécurité humaine est un concept qui a été formellement dégagé du rapport sur le développement humain du PNUD de 1994. Présentée par ce dernier comme une alternative au développement humain, la sécurité humaine a été institutionnalisée davantage comme une réponse aux préoccupations contemporaines en termes de sécurité globale et de bien être des individus, et comme un levier de garantie de la paix internationale.Dans la dynamique de la sécurité humaine, il sera observé une mutation du système normatif international par le renforcement de la place des droits de l’Homme et du droit international humanitaire dans l’ordre juridique. Aussi, la nécessité de la sécurité humaine va entrainer une nouvelle conception de l’objet de la sécurité collective. À cet effet, les Nations unies joueront un rôle déterminant en ce qu’elles vont développer de nouvelles compétences (en termes de garantie de la paix) et de nouvelles activités relatives à la sécurité humaine. Cet élan, d’une part, dynamisera un grand nombre d’acteurs internationaux qui s’investiront en faveur de la sécurité et de la protection des individus et, d’autre part, suscitera l’établissement de nouveaux mécanismes de paix et de sécurité internationales / Human security is a concept that was officially drawn out in the UNDP’s 1994 report on human development. In this report the concept was introduced as an alternative to human development and then became institutionalised as a response to contemporary preoccupations related to security matters. Human security therefore relates to threats to individuals, which are not only different to those that jeopardise State security but relate to the physical security and well-being of individuals.International peace and security factors were subsequently revised from a conceptual perspective, shifting from a State security-based focus to a focus on the global security of individuals.In the dynamics of human security, the international order’s normative system is shifting, especially owing to the growing importance of human rights and international humanitarian law in the legal order. Similarly, ensuring human security will redefine the objectives and activities of collective security. In this respect, the United Nations plays a crucial role. The Organisation will develop new competences in terms of peacekeeping and will carry out new operations for the benefit of human security. This renewed effort will reinforce many international stakeholders who will develop competences and establish organisations to contribute significantly to the security and protection of individuals and larger to the international peace