For most Americans, habeas corpus is the cornerstone of our legal system: the principal constitutional check on arbitrary government power, allowing an arrested person to challenge the legality of his detention. In a study that could not be more timely, Justin Wert reexamines this essential individual right and shows that habeas corpus is not necessarily the check that we've assumed. Habeas corpus, it emerges, is as much a tool of politics as it is of law.