How do leaders of an alliance manage crises in which the interests of the members of an alliance conflict with each other while, at the same time, maintaining the functioning of an alliance? This thesis seeks to make a contribution towards better a understanding of allies' crisis behaviour and offers a new model to explain this. In order to undertake the study, four crises in the US-UK 'Special Relationship' during the Reagan-Thatcher years (198 1-1988) have been selected: the Faildands War 1982, the US invasion of Grenada in 1983, the US air raids on Libya in 1986, and finally the Persian Gulf reflagging operation of 1987. The particular focus is upon the way in which crises were managed by the two governments and how these events impacted upon their wider relationship. It also argues that the nature of a certain type of crisis undermines the Anglo-American special relationship. By examining and analysing the allies' crisis behaviour in these four case studies, this thesis tries to determine whether the relationship between the two allies enabled them to co-operate more effectively in times of crisis.