The writ of habeas corpus (which is roughly translated from the Latin as “you should have the body”) is considered a cornerstone of due process of law. It means that a person cannot be detained unless he or she is brought in person before the court so the court can determine whether or not the person is being lawfully held.

The notion dates back to medieval England; many historians believe that habeas corpus was implied by the Magna Carta (1215)—Article 39 states, “No freemen shall be taken or imprisoned….or exiled or in any way destroyed … except by the lawful judgment of his peers or by the law of the land.” The writ was reinforced by Britain’s Habeas Corpus Amendment Act of 1679, which stated that the Crown (king or queen) cannot detain a prisoner against the wishes of Parliament and the courts. The English introduced the concept in the American colonies. And when the U.S. Constitution (1788) was written, it declared (in Article I, Section 9) that habeas corpus “shall not be suspended, unless when in cases of rebellion or invasion the public safety may require it.” For example, during the Civil War (1861–65), President Abraham Lincoln (1809–1865) suspended habeas corpus; and during Reconstruction (1865–77), it was again suspended in an effort to combat the activities of the Ku Klux Klan.