Habeas Corpus, a writ (written order) issued by a judge ordering that a person being held in custody be brought into court to determine whether he or she is being held lawfully. (The term habeas corpus is Latin, and means “you should have the body.”) The purpose of habeas corpus is to prevent a person from being deprived of liberty without due process. The prisoner appeals to a judge, who orders the person who has custody of the prisoner to have him or her brought before the court. The person must be released if the judge finds the detention to be unlawful.

Habeas corpus developed as part of the English common law and appeared in the 14th century. In 1679, Parliament passed the Habeas Corpus Act, which enshrined the principle in law. The English colonists in America regarded habeas corpus as one of the “dearest birthrights of Britons,” and it was incorporated into the U.S. Constitution and into state constitutions.

The U.S. Constitution provides that “the privilege of the writ of habeas corpus shall not be suspended, unless when in cases of rebellion or invasion the public safety may require it” (Article I, Section 9). The federal courts have agreed that Congress may suspend the writ but have disagreed over whether the President may do so. At the start of the Civil War, President Lincoln authorized suspension of the writ in some instances; Congress later gave him the power to suspend it at any time during the war.

In the United States, the Military Commissions Act of 2006 allows controversial practices for the detention, interrogation, and treatment of terrorist suspects. The act originally suspended habeas corpus for imprisoned suspects, but the right was restored by the Supreme Court in 2008.