what allegations it must contain are questions which a federal
court alone determines.[983] Equally subject to condemnation is the
practice of the warden of a State penitentiary who denied prisoners
access to the courts unless they procured counsel to represent
them.[984]

Appeals; Corrective Process.--Rehearing, new trials, and
appeals are not considered to be essential to due process; and a State
is forbidden by no provision of the Constitution from vesting in one
tribunal the final determination of legal questions. Consequently, a
review by an appellate court of a final judgment in a criminal case,
irrespective of the gravity of the offense, is wholly within the
discretion of the State to allow or not to allow;[985] and, if granted,
may be accorded by the State upon such terms as in its wisdom may be
deemed proper.[986] "Wide discretion must be left to the States for the
manner of adjudicating a claim that a conviction is unconstitutional;
* * * and so long as the rights under the * * * Constitution may be
pursued, it is for a State and not for * * * [the Supreme] Court [of the
United States] to define the mode by which they may be vindicated. * * *
A State may decide whether to have direct appeals * * *, and if so under
what circumstances * * * may provide that the protection of
[constitutional] rights * * * be sought through the writ of _habeas
corpus_ or _coram nobis_, [or] * * * may afford remedy by a simple
motion brought either in the Court of original conviction or at the
place of detention."[987]

However, if the tribunal of first instance fails to accord due process
such as occurs when the Court in which a conviction is obtained is
dominated by a mob, the State must supply corrective process. Moreover,
when such process is made available, the corrective proceedings in the
reviewing or appellate tribunal being no less a part of the process of
law under which a defendant is held in custody, become subject to
scrutiny on the occasion of any determination of an alleged
unconstitutional deprivation of life or liberty.[988] Such examination
may lead unavoidably to substantial federal intervention in State
judicial proceedings, and sensitive, no doubt, to the propriety
thereof,[989] the Supreme Court, almost until Brown _v._
Mississippi,[990] decided in 1936, manifested an unusual reluctance to
indulge in an adverse appraisal of the adequacy of a State's corrective
process.

Prior to the latter date, the Court