Despite the upsurge in the literature on third party intervention in recent years, particularly that relating to mediation, there is still a significant gap in the field. While some theoretical accounts content themselves with describing the qualities of an ideal mediator, other studies borrow examples from a variety of case studies to emphasise the wide range of the mediator's functions or the tactics it can use. What is missing is a systematic, case study-driven analysis that draws on the theoretical literature while generating some fresh propositions about the conditions that are propitious for successful mediation. The article aims to achieve this by proposing three hypotheses about the impact of power, impartiality and timing on the mediation process: (1) The more power (leverage) the mediator has over the disputants, the more likely it is to succeed. (2) The more impartial the mediator is, the more likely it is to succeed. (3) Mediation is more likely to succeed when the conflict has reached an escalatory stage. These hypotheses will be tested against the experience of four successful cases of third party intervention in the Arab–Israeli conflict, which over the past six decades has experienced a multitude of mediators of different types.