opinion: Mr. Justice Black
  delivered the opinion of the Court.
  Petitioner was convicted of murder in a Georgia state court. His sentence was death by electrocution. Subsequently he asked the Governor to postpone execution on the ground that after conviction and sentence he had become insane. Acting under authority granted by § 27-2602 of the Georgia Code the Governor appointed three physicians who examined petitioner and declared him sane. Petitioner then filed this habeas corpus proceeding again alleging his insanity. He contended that the due process clause of the Fourteenth Amendment required that his claim of insanity after sentence be originally determined by a judicial or administrative tribunal after notice and hearings in which he could be represented by counsel, cross-examine witnesses and offer evidence. He further contended that if the tribunal was administrative its findings must be subject to judicial review. The trial court sustained the constitutional validity of § 27-2602, holding that determination of petitioner’s sanity by the Governor supported by the report of physicians had met the standards of due process. The State Supreme Court affirmed, 205 Ga. 122, 52 S. E. 2d 433. The constitutional questions being substantial, see Phyle v. Duffy, 334 U. S. 431, 439, the case is here on appeal under 28 U. S. C. § 1257 (2).
  In affirming, the State Supreme Court held that a person legally convicted and sentenced to death had no statutory or constitutional right to a judicially conducted or supervised “inquisition or trial” on the question of insanity subsequent to sentence. It viewed the Georgia statutory procedure for determination of this question as motivated solely by a sense of “public propriety and decency” — an “act of grace” which could be “bestowed or withheld by the State at will” and therefore not subject to due process requirements of notice and hearing. The court cited as authority, among others, our holding in Nobles v. Georgia, 168 U. S. 398. Compare Burns v. United States, 287 U. S. 216, 223.
  In accordance with established policy we shall not go beyond the constitutional issues necessarily raised by this record. At the outset we lay aside the contention that execution of an insane person is a type of “cruel and unusual punishment” forbidden by the Fourteenth Amendment. See Francis v. Resweber, 329 U. S. 469. For the controlling Georgia statutes neither approve the practice of executing insane persons, nor is this petitioner about to be executed on such a premise. It is suggested that the reasoning of the Georgia Supreme Court in this case requires us to pass upon the state statute as though it had established a state practice designed to execute persons while insane. But we shall not measure the statute by some possible future application. Our holding is limited to the question of whether the method applied by Georgia here to determine the sanity of an already convicted defendant offends due process.
  Postponement of execution because of insanity bears a close affinity not to trial for a crime but rather to reprieves of sentences in general. The power to reprieve has usually sprung from the same source as the power to pardon. Power of executive clemency in this country undoubtedly derived from the practice as it had existed in England. Such power has traditionally rested in governors or the President, although some of that power is often delegated to agencies such as pardon or parole boards. Seldom, if ever, has this power of executive clemency been subjected to review by the courts. See Ex parte United States, 242 U. S. 27, 42, and cases collected in Note, 38 L. R. A. 577, 587.
  We are unable to say that it offends due process for a state to deem its Governor an “apt and special tribunal” to pass upon a question so closely related to powers that from the beginning have been entrusted to governors. And here the governor had the aid of physicians specially trained in appraising the elusive and often deceptive symptoms of insanity. It is true that gov'ernors and physicians might make errors of judgment. But the search for truth in this field is always beset by difficulties that may beget error. Even judicial determination of sanity might be wrong.
  Recently we have pointed out the necessary and inherent differences between trial procedures and post-conviction procedures such as sentencing. Williams v. New York, 337 U. S. 241. In that case we emphasized that certain trial procedure safeguards are not applicable to the process of sentencing. This principle applies even more forcefully to an effort to transplant every trial safeguard to a determination of sanity after conviction. As was pointed out in the Nobles case, supra, to require judicial review every time a convicted defendant suggested insanity would make the possibility of carrying out a sentence depend upon “fecundity in making suggestion after suggestion of insanity.” Nobles v. Georgia, supra, at 405-406. See also Phyle v. Duffy, supra. To protect itself society must have power to try, convict, and execute sentences. Our legal system demands that this governmental duty be performed with scrupulous fairness to an accused. We cannot say that it offends due process to leave the question of a convicted person’s sanity to the solemn responsibility of a state’s highest executive with authority to invoke the aid of the most skillful class of experts on the crucial questions involved.
  This leaves the contention that the Georgia statutes do not make provisions for an adversary hearing in which a convicted defendant can be present by friends, attorneys, or in person, with the privilege of cross-examining witnesses and offering evidence. Whether this Governor declined to hear, any statements on petitioner’s behalf, this record does not show. We would suppose that most if not all governors, like most if not all judges, would welcome any information which might be suggested in cases where human lives depend upon their decision.
  Both the Nobles and the Phyle cases stand for the universal common-law principle that upon a suggestion of insanity after sentence, the tribunal charged with responsibility must be vested with broad discretion in deciding whether evidence shall be heard. This discretion has usually been held nonreviewable by appellate courts. The heart of the common-law doctrine has been that a suggestion of insanity after sentence is an appeal to the conscience and sound wisdom of the particular tribunal which is asked to postpone sentence. We cannot say that the trust thus reposed in judges should be denied governors, traditionally charged with saying the last word that spells life or death. There is no indication that either the Governor or the physicians who acted on petitioner’s application violated the humanitarian policy of Georgia against execution of the insane. We hold that the Georgia statute as applied is not a denial of due process of law.
  Affirmed.
  Mr. Justice Douglas took no part in the consideration or decision of this case.
  “Disposition of insane convicts. . . . Upon satisfactory evidence being offered to the Governor that the person convicted of a capital offense has become insane subsequent to his conviction, the Governor may, within his discretion, have said person examined by such expert physicians as the Governor may choose; and said physicians shall report to the Governor the result of their investigation; and the Governor may, if he shall determine that the person convicted has become insane, have the power of committing him to the Milledgeville State Hospital until his sanity shall have been restored, as determined by laws now in force. . . .” Ga. Code Ann. § 27-2602 (1074 P. C.); Acts 1903, p. 77.
  “No person who has been convicted of a capital offense shall be entitled to any inquisition or trial to determine his sanity.” Ga. Code Ann. § 27-2601 (1073 P. C.); Acts 1903, p. 77.
  Nobles v. Georgia, 168 U. S. 398,409.
  See eases collected in Notes, Ann. Cas. 1916E, 424 et seq.; 49 A. L. R. 801 et seq.; 38 L. R. A. 577 et seq.
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