The external dimension. of the failed Middle East Peace Process had previously garnered only minimal academic attention. In some respects then one of the most studied conflicts in the globe was a form of terra incognita when it came to the thorny issue of the world's most powerful international state actor and its mediation role in the Palestinian-Israeli conflict. The purpose of this case study is therefore to examine U.S. mediation in the conflict and whether it contributed to the collapse of the peace process. This study holds that much of the traditional theoretical literature on international mediation fails to address the dynamics of biased mediation with particular emphasis on mediator leverage. Conventional theories on mediation have indicated that mediator bias can be an important basis of influence, contributing to positive outcomes; the more power or leverage a mediator possesses the more likelihood of success in mediation. Significantly, if the U.S. has this apparent influence, leverage and power, why was it unable as a powerful mediator to be more productive in the Palestinian-Israeli conflict? In contrast, the findings in this study point to the problematical concept of leverage, especially when bias is entrenched in the mediation process itself. Supplied by The British Library - 'The world's knowledge' 1 The main results can be summarised as follows; the reliance on the power brokerage argument or seeing mediators as having leverage and influence is overrated in international mediation. The u.s. as a biased mediator was predominately unwillingly to use leverage in mediation for fear of damaging its 'special relationship' with Israel. As a consequence, biased mediation does not necessarily denote success and mediators who maintain their bias throughout the process hinder prospects for peace and contribute to failed mediation. In the case of U.S. mediation in the Palestinian-Israeli conflict, bias almost always supersedes leverage.