This book is concerned with the issue of power and the manner and form of its exercise in Japan between the fall of the last Tokugawa Shogun and 7 December 1941, and in American military commissions, and before and by the International Military Tribunal for the Far Eastwhich sat in Tokyo between April 1946 and November 1948, and by General Douglas MacArthur in December 1948, when he gave the order which resulted in the killing of Koki Hirota, well after the Pacific War had concluded. Koki Hirota, former Premier of Japan, was charged, together with 27 others, of having conspired to commit war crimes, crimes against peace: and murder. The thesis examines aspects of the rich traditional culture of Japan, its religions, its philosophies and methods of government, and the means whereby cabinet government functioned in the decade prior to 7 December 1941. It also examines the issue of the jurisdiction of the Tribunal established to try him and the review process undertaken thereafter by MacArthur. In order to ascertain the ambit of the powers said by MacArthur to have been lawfully invoked by him. The book explores the history of military commissions in America and the exercise by him of powers sufficient to allow him to issue orders for the execution of a civilian who took no part in the government of his country at the commencement of, or during the Pacific War. Conclusions Hirota acted within power, within the constraints of his country's political processes, and was subject in international law only to the municipal laws of Japan. He committed no war crime. If he conspired with any-one it was in what he believed were in the best interests of his Emperor and Japan. The Tribunal established by MacArthur was not an international court of any kind. It was convened to administer punishment to people who the Allied governments believed to have been guilty of war crimes. It rendered judgment as might have been anticipated. It acquitted no-one. In ordering the execution of Hirota, MacArthur acted in a manner consistent with the arbitrary procedures established by American military commissions. But by following that procedure he placed himself outside the protection in law afforded to an ordinary soldier who kills during a war. Only municipal law can confer defenses open to one who kills another. MacArthur neither had nor could he exercise, any of the judicial power of America. He neither had nor could he exercise any of the judicial power of the Emperor of Japan The killing of Hirota by MacArthur was not an act lawfully authorized, justified or excused by law.