FOR more than six hundred years that is, since Magna Carta, in 1215 there has been no clearer principle of English or American constitutional law, than that, in criminal cases, it is not only the right and duty of juries to judge what are the facts, what is the law, and what was the moral intent of the accused; but that it is also their right, and their primary and paramount duty, to judge of the justice of the law, and to hold all laws invalid, that are, in their opinion, unjust or oppressive, and all persons guiltless in violating, or resisting the execution of, such laws.So begins Spooner's epic on the jury, its origins and history. Spooner examines the history and powers of a jury, from the magna carta in King John's time, to the practices in the 18th century. A classic work on law, Spooner argues that the decision of the jury is sovereign over the king's law.