During the Cold War, the conduct of international relations was focused on the challenge of the "strong state," that is, the state with the capacity and ambition to project its influence beyond its sovereign territory by military means. In such a setting, peace and security concerns dominated the political imagination, and such ideas as "containment" and "deterrence" were the core of global policy. In the post-Cold-War world,1 the challenge of the "weak state" has become a recurrent center of concern. A weak state is a state that is in the grips of a war of internal fragmentation or that is in any sense ungovernable, as a consequence of civil strife, overwhelming humanitarian crisis and even the collapse of minimal capacity to provide "law and order." Fashioning appropriate responses to the challenges posed by weak states remains controversial and reflects the transitional nature of the post-Cold-War world. Unlike the simplicities of the Cold War, the distinctive nature of each weak state challenge makes issues of interpretation of crucial importance. This chapter discusses international humanitarian diplomacy as the response mode to the challenges posed by various weak state emergences.