The President was assassinated at a theatre in the city of Washington. At the time of the assassination a civil war was flagrant,--the city of Washington was defended by fortifications regularly and constantly manned, the principal police of the city was by federal soldiers, the public offices and property in the city were all guarded by soldiers, and the President's house and person were, or should have been, under the guard of soldiers. Martial law had been declared in the District of Columbia, but the civil courts were open and held their regular sessions, and transacted business as in times of peace. Such being the facts, the question is one of great importance,--important because it involves the constitutional guarantees thrown about the rights of the citizen, and because the security of the army and government in time of war is involved; important, as it involves a seeming conflict between the laws of peace and war. Having given the question propounded the patient and earnest consideration its magnitude and importance require, I will proceed to give the reasons why I am of the opinion that the conspirators not only may but ought to be tried by a military tribunal. A civil court of the United States is created by a law of Congress, under and according to the Constitution. To the Constitution and the law we must look to ascertain how the court is constituted, the limits of its jurisdiction, and what its mode of procedure. A military tribunal exists under and according to the Constitution in time of war. Congress may prescribe how all such tribunals are to be constituted, what shall be their jurisdiction and mode of procedure. Should Congress fail to create such tribunals, then, under the Constitution, they must be constituted according to the laws and usages of civilized warfare. They may take cognizance of such offences as the laws of war permit; they must proceed according to the customary usages of such tribunals in time of war, and inflict such punishments as are sanctioned by the practice of civilized nations in time of war. In time of peace, neither Congress nor the military can create any military tribunals, except such as are made in pursuance of that clause of the Constitution which gives to Congress the power "to make rules for the government of the land and naval forces." I do not think that Congress can, in time of war or peace, under this clause of the Constitution, create military tribunals for the adjudication of offenses committed by persons not engaged in, or belonging to, such forces.