When can a state give political support to a military intervention in another state? The Government of the Netherlands commissioned an Expert Group to examine this complex, topical and time-sensitive question and to consider whether it should press for international acceptance of humanitarian intervention as a new legal basis for the use of force between states in exceptional circumstances. This volume is the result of those efforts. The Expert Group was led by Professor Cyrille Fijjnaut and consisted of Mr. Kristian Fischer, Professor Terry Gill, Professor Larissa van den Herik, Professor Martti Koskenniemi, Professor Claus Kreß, Mr. Robert Serry, Ms. Monika Sie Dhian Ho, Ms. Elizabeth Wilmshurst and Professor Rob de Wijk. Their thorough analysis and recommendations offer important insights that can aid governments in formulating a position on political support for the use of force between states and humanitarian intervention. The volume also constitutes a useful tool for scholars and practitioners in considering these difficult and important issues.