This book examines US hegemony and international legitimacy in the post-Cold War era, focusing on its leadership in the two wars on Iraq. The preference for unilateral action in foreign policy under the Bush Administration, culminating in the use of force against Iraq in 2003, has unquestionably created a crisis in the legitimacy of US global leadership. Of central concern is the ability of the United States to act without regard for the values and interests of its allies or for international law on the use of force, raising the question: Does international legitimacy truly matter in an international system dominated by a lone superpower? US Hegemony and International Legitimacy explores the relationship between international legitimacy and hegemonic power through an in depth examination of two case studies - the Gulf Crisis of 1990-91 and the Iraq Crisis of 2002-03 - and examines the extent to which normative beliefs about legitimate behaviour influenced the decisions of states to follow or reject US leadership. The findings of the book demonstrate that subordinate states play a crucial role in consenting to US leadership and endorsing it as legitimate and have a significant impact on the ability of a hegemonic state to maintain order with least cost. Understanding of the importance of legitimacy will be vital to any attempt to rehabilitate the global leadership credentials of the United States under the Obama Administration.