Understanding the workings of interstate cooperation in defence: an exploration into Franco-British cooperation after the signing of the Lancaster House Treaty

Cooperation occurs more often than conflict in the international system. However, its practicalities have been little conceptualised in International Relations. Through an empirical study of the workings of contemporary Franco-British cooperation in defence, this article offers a multidimensional analysis of interstate cooperation taking into account organisational, political, material and cognitive factors. By studying their centripetal and centrifugal effects, this article shows why each factor is relevant for understanding what favours and impedes the emergence and continuation of intergovernmental cooperation. It notably demonstrates how domestic interorganisational dynamics have an impact on relations with foreign partners. This article also shows how bridging the traditional divide between approaches based on interests and approaches based on beliefs allows us to identify the evolutionary dynamic of cooperation.