This book analyses States resistance to United Nations Security Council resolutions and puts forward a theory of lawful resistance. The book explores a number of case studies of individual and collective State resistance to mandatory Council resolutions, expressly justified by the alleged unlawfulness of the opposed resolution. The book develops the concept of lawful resistance including the cues of unlawfulness upon which the resisting State can rely so as to assess the lawfulness and legitimacy of its arguments, the role played by the different actors present in the different contexts of resistance, as well as the contours of behaviour that may qualify as lawful resistance.