In this issue of the Review, we invited two experts in international humanitarian law (IHL) and multinational peace operations – Professor Eric David and Professor Ola Engdahl – to debate on the way in which the involvement of a multinational force may affect the classification of a situation. This question is particularly relevant to establishing whether the situation amounts to an armed conflict or not and, if so, whether the conflict is international or non-international in nature. This in turn will determine the rights and obligations of each party, especially in a context in which multinational forces are increasingly likely to participate in the hostilities.