This book examines US recourse to military force in the post-9/11 era. In particular, it evaluates the extent to which the Bush and Obama administrations viewed legitimizing the greater use-of-force as a necessary solution to thwart the security threat presented by global terrorist networks and WMD proliferation. The Bush administration's use-of-force policy centered on advocating preemptive self-defence options, which were really preventive in nature. For example, it is argued that they responded to potential long-term threats based on ambiguous evidence. Central to this cloaking of preventive options in the more legitimate language of preemptive self-defence was an expanded notion of what counts as an imminent threat. Despite the Obama administration's avowal to multilateralism and professed US adherence to global norms, it did not expressly reject his predecessor's reasoning on the preemptive/preventive use-of-force. Indeed, the Administration's counter-terrorist campaign against Al Qaeda and in particular its drone program made the use-of-force in self-defence a widespread, regular, even commonplace occurrence during Obama's tenure. Despite being positioned at different points on the political spectrum, the book therefore concludes that Bush and Obama have chosen a remarkably similar approach towards expanding the use-of-force in self-defence.

Aiden Warren is Senior Lecturer in the School of Global, Urban and Social Studies at RMIT University in Melbourne, Australia. His research interests are in the areas of International Security, US national security and foreign policy, US Politics, International Relations, and issues associated with Weapons of Mass Destruction, proliferation, non-proliferation and arms control. He is the author of The Obama Administration's Nuclear Weapon Strategy: the Promises of Prague and Prevention, Pre-emption and the Nuclear Option: From Bush to Obama.

Ingvild Bode is JSPS Postdoctoral Fellow in the Institute for Sustainability and Peace at the United Nations University in Tokyo, Japan. Her research interests are in the areas of understanding individual agency, norm and policy change at the UN, international humanitarian law and the United Nations system. She is the co-author of Key Concepts in International Relations (with Thomas Diez and Aleksandra Fernandes da Costa).

Introduction
1. The International Legal Paradigm: The UN Charter jus ad bellum Regime
2. Self-Defence in International Law: Pre-emptive/Preventive Requisites
3. Preventive and Pre-emptive Self-Defence in US National Security Policy: A Brief History
4. Bush and the Use-of-Force
5. Obama and the Use-of-Force
6. The Rise of Drones
Conclusion – The Use-of-Force and the Making of Hegemonic International Law: from Bush to Obama