Section 2241 of Title 28 of the United States Code requires that a petitioner for a writ of habeas corpus be "in custody." As a corollary of the "custody" requirement, the common law tradition required that the effect of the writ must be the petitioner's "release from custody.'' Because the United States Constitution and the federal habeas corpus statutes guarantee the availability of the writ in general terms, it is to the common law that the courts have consistently turned for the definition of these terms and for the restrictive effect of these requirements on the availability of the writ in particular situations. However, recent decisions by the Court of Appeals for the Fourth Circuit and the Pennsylvania Supreme Court have questioned the continued viability of the common law approach.
Michigan Law Review,
Habeas Corpus--Custody and Release From Custody Requirements of Habeas Corpus--Viability of McNally v. Hill in the Moden Context,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol65/iss1/7