State Accountability under International Law sets forth a definition of State accountability as the antithesis of State impunity, and establishes a threshold against which the existence, or not, of State accountability can be determined. The book draws together the many academic theories relating to accountability that have arisen in various areas of international law including environmental law, human rights and trade law before going on to examine an emerging practice of State accountability. A variety of ad hoc attempts and informal mechanisms are assessed against the threshold of State accountability established with emphasis being given to practical examples ranging from the accountability of Germany and Japan after World War Two to the current attempts to prevent impunity by Sudan and Zimbabwe. The book also addresses the relationship between State accountability and the emerging practice of international humanitarian intervention to consider whether intervention could be used for the purpose of holding States accountable for a breach of jus cogens norms.