The chief conspirators, on whom rested the responsibility of the plot, were still at large, and in an attitude of desperate hostility towards the government. The extent of their plans, and the means at their command for their execution, could not be known, and so it was a matter of the utmost importance to deal with the prisoners in the most summary manner consistent with the ends of justice. The President requested the attorney general, Hon. James A. Speed, a Kentuckian by birth, to give his official opinion as to whether these persons implicated in this crime could be tried before a military tribunal, or must be tried before a civil court. As the reply of the Attorney General furnishes an exhaustive discussion of the different conditions existing under a state of peace and a state of war, and shows that whilst in a state of peace the Constitution throws its shield of protection over the life, liberty, and property of the citizen, even the humblest, its provisions cannot afford protection to these in a state of war, and that martial law, or the common law of war comes in in the place of the Constitution to ameliorate as much as possible the miseries of war, and secure, as far as possible, the ends of justice and mercy; and as it constitutes a most important and interesting document worthy of the careful study of every young man who desires to become well informed on the most important questions of our national life, I shall give it a place entire, and commend it to careful perusal and study. _Opinion of the Attorney General._