Federal habeas corpus is a procedure under which a federal court may review the legality of an individual's incarceration. It is a cornerstone of justice and personal liberty in the U.S. legal system.The term is Latin for "you must have the body. A Writ of Habeas Corpus is mentioned in the U.S. Constitution in Article I, Section 9, Clause 2. Federal criminal defense explains a federal Habeas Corpus petition, a legal remedy to protect against someone's unlawful and indefinite imprisonment. Though subject to different rules, incarcerated people in both state or federal custody may petition for a federal writ of habeas corpus. What Is Habeas Corpus?