Although the topic of international mediation has been debated frequently amongst academic scholars, most literature has failed to address the notion of threat perception. This thesis examines the impact of threat perceptions from ideational and material force on the prospects for successful international mediation. In this comparative case study, I argue that threat perception is an influential factor conditioning the road towards peace agreements, by examining one case of failure and one case of success in international mediation of interstate conflicts. The first case in the comparison consists of the conflict between Armenia-Azerbaijan in the disputed region of Nagorno-Karabakh, where the OSCE Minsk Group has conducted mediation efforts. The second case examined is the conflict between Israel-Egypt which predominately have been mediated by the US. A conflict which ending was marked by the Camp David Accords in 1978 and resulted in a peace treaty the year after. The analysis shows that threat perception is indeed a factor of importance for outcome in relation to international mediation. Compared to previous research largely focused on material factors, the result shows that ideational factors should be considered to the same extent and are influential in both cases. This contribution to the field of war studies and international mediation literature also reflects the interconnectivity between threat perceptions from ideational and material force. An insight which I argue is pivotal for the comprehension of why some interstate conflicts appear to be resistant to resolution.