Mr. Justice Harlan
delivered the opinion of the court.
The principal contention of the appellant is, that the. court martial convened under the order of Rear Admiral Crosby was an illegal body, without jurisdiction to try him. This contention is based upon the fact that of the seven members of the court participating in the trial, 'five were his juniors in rank. Our attention has been called to the clause -of the 5th section of the army appropriation act of July 13, 1866, 14 Stat. 92, c. 176, preserved in § 1229 of the Revised Statutes providing that "no officer in the military or naval service shall, in time of peace, be dismissed from service, except upon and in pursuance of the sentence of a court martial to that effect or in commutation thereof." And article 36, for the government of the Navy, Rev. Stát. § 1624, reads: " No officer shall be dismissed from the naval service except by the order of the President or by sentence of a general court martial; and in time of peace no officer shall be dismissed except in pursuance of the sentence of a general court martial or in mit-. igation thereof." Article 39 of section 1624 of the Revised Statutes provides: " A general court martial shall consist of not more than thirteen nor less than five commissioned officers as members: and as many officers, not exceeding thirteen, as can be convened without injury to the service, shall be summoned on every such court. But in no case where it can be avoided without injury to the service, shall more than one-half, exclusive of the President, be junior to the officer to be tried. Thfe senior officer, shall always preside, and the others shall take place according to their rank."
These provisions are cited by the appellant in support of his contention that the court martial at Hong-Kong was an illegal tribunal. He insists that it appears from the record before us that a court consisting of not less than five commissioned officers — more than one-half of them, exclusive of the President, being his seniors in rank — could have been convened without injury to the service, and therefore the court which tried him was unauthorized by the statute. This is supposed to be established by the fact that, at the time of the organization of the court at Hong-Kong, there were twelve naval officers, Superior in rank to the appellant, on waiting orders-in the city of Washington. But this does not show that any of those officers could at-that time have been sent from the national capital to the Asiatic station "without injury to the service." The public interests may have required them to be held at Washington for assignment to other duty than service upon the court martial to be convened for the trial of the appellant. Of that the Navy Department was necessarily the judge, and its discretion could not be controlled nor its action reviewed by the courts. The presence of those officers in Washington, on waiting orders, at the time the court martial at TIong-Kong was ordered, must be conclusively presumed to have been required by the Navy Department, and, therefore, by the exigencies of the naval service. Some stress is laid upon the circumstance, stated in the findings of the court below, that certain officers were detailed by the Navy Department, in November, 1883, to proceed from New York to Panama for service upon a court martial, ordered for the trial of a,medical inspector; such detail being deemed necessary by reason of, the fact that in the squadron to which the inspector was attached there were not "the requisite number of officers of sufficient rank to organize a court martial " to try him. But that only tends to show that a court martial, a majority of whose members, exclusive of the President, were senior in rank to the inspector could, at that time, be convened " without injury to the service." It does not show what were' the requirements of the service át the time the court martial was ordered to be held at Hong-Kong in May, 1883, for the trial of the appellant. Ik results that there is no ground for the contention that the record shows that the organization of a court, with more than one-half of its members junior in rank to appellant, could have been avoided without injury to the service.
. The statute permits an officer of the navy to be tried by a court-martial, more than one-half of whose members are his juniors in rank, if it cannot be avoided without injury to the service. Bear Admiral 'Crosby, being commander-in-chief of a squadron not operating or. stationed " in the waters of the United States," had the power, without express author-: ity from the President, to convene a general court martial for the- trial of the appellant. Kev. Stat. § 1624, Art. 38. That is-not disputed. Whether the interests of the service admitted of a postponement of his trial until a court could be organized of which' at least one-half of its members, exclusive of the President, would be his seniors in rank, or' whether the interests of the service-required a prompt trial, upon the charges preferred, by such officers as could be then assigned to that duty by the commander-in-chief, of the squadron, were matters committed by the statute to the determination of that officer. And the courts must assume — nothing to the contrary appearing upon the face of the order convening the court — that the discretion conferred upon him was properly exercised, and, therefore, that the trial of the appellant by a court, the majority of whom were his juniors in rank, could not be avoided " without injury to the service." " Whenever," this court said in Martin v. Mott, 12 Wheat. 19, 31, " a statute gives a discretionary power to any person, to be exercised by him upon his own opinion of certain facts, it is a sound rule of construction, that the statute constitutes him the sole and exclusive judge of the existence of those facts."
The result of these views is that the sentence of the court martial, and its approval by the President, cannot be regarded as void.
But, independently of the question as to the legal character of the court martial, there is another ground upon which the affirmance of the judgment of the Court of Claims can rest. In Blake v. United States, 103 U. S. 227, 235, it was held, upon full consideration, that the fifth section of the army appropriation act of July 13, 1866, c. 176, 14 Stat. 92, above quoted, meant, "that whereas, under the act of July 17, 1862, as well as before its passage, the President alone was authorized to dismiss an army or naval officer from the service' for any cause which, in his judgment, either rendered such officer unsuitable for, or whose dismissal would promote, the public service, he alone shall not, thereafter, in time of peace, exercise such power of dismissal, except in pursuance o'f a court martial sentence to that'effect or in commutation thereof." Again, in the same case: " Our conclusion is that there was no purpose, by the fifth section of the act of July 13, 1866, to withdraw from the President the power, with the advice and consent of the Senate, to supersede an officer in the military or naval service by the appointment of some one in his place. If the power of the President and Senate, in this regard, could be constitutionally subjected to restrictions by statute, (as to which we express no opinion,) it is sufficient for the present case to say that Congress did not intend by that section to impose them. It is, in substance and effect, nothing more than a declaration that the power theretofore exercised by the President, without the concurrence of the Senate, of summarily dismissing or discharging officers of the Army or Navy, whenever in his judgment the interest of the service required it to be done, shall not exist, or be exercised, in time of peace, except in pursuance of the sentence of a court martial, or in commutation thereof. There was, as we think, no intention to deny or restrict the power of the President, by and with the advice and consent of the Senate, to displace them by the appointment of others in their places." '
These principles were affirmed in the subsequent case of Keyes v. United States, 109 U. S. 336, 339.
In view of these adjudications, the judgment below may be sustained without reference to the inquiry whether the court martial that tried Mullan was legally constituted, or whether he ceased to be an officer of the Navy in consequence of the approval of the sentence by the President. The fact appears that Francis M. Green, under the appointment of the President, by and with the advice and consent of the Senate, was commissioned commander in place of Eastman retired, and Mullan dismissed. The circumstance that Green was appointed in place of one commander retired, and another dismissed, is explained by the naval appropriation act of August 5, 1882, c. 391, 22 Stat. 284, 286,- requiring a reduction of the number of officers in certain grades of the Navy, including the grade of commander. Green was appointed by the President, by and with the advice and consent of the Senate, and was-commissioned, in place of Mullan. This, under the above decisions, to which we adhere, put Mullan out of the Navy,, even if the proceedings of the court martial had been void.
Judgment affirmed.