habeas corpus (hā´bēəs kôr´pəs) [Lat.,=you should have the body], writ directed by a judge to some person who is detaining another, commanding him to bring the body of the person in his custody at a specified time to a specified place for a specified purpose. The writ's sole function is to release an individual from unlawful imprisonment; through this use it has come to be regarded as the great writ of liberty. The writ tests only whether a prisoner has been accorded due process, not whether he is guilty. The most common present-day usage of the writ is to appeal state criminal convictions to the federal courts when the petitioner believes his constitutional rights were violated by state procedure. An individual incarcerated in a state prison is expected to exhaust all possible routes available before applying to a federal judge for habeas corpus.
The term is mentioned as early as the 14th cent. in England, and was formalized in the Habeas Corpus Act of 1679. The privilege of the use of this writ as a safeguard against illegal imprisonment was highly regarded by the British colonists in America, and wrongful refusals to issue the writ were one of the grievances before the American Revolution. As a result, the Constitution of the United States 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 1, Section 9). President Lincoln suspended habeas corpus in 1861 at the beginning of the Civil War, and his decision was upheld by Congress—despite protests by Chief Justice Roger Taney that such suspension was not within the powers of the president. The Supreme Court's liberal decisions in the 1950s and 1960s in the area of prisoners' rights encouraged many incarcerated persons to file writs challenging their convictions, but the Court under William Rehnquist limited multiple habeas corpus filings, particularly from prisoners on death row.
See P. D. Halliday, Habeas Corpus: From England to Empire (2010); J. J. Wert, Habeas Corpus in America (2011).