Seddon attempted to reverse the facts, to show that the importance of the Mississippi in commerce was a Northern not a Southern concern. He threw light upon the tactics of the time by his description of the future action of Confederate sharpshooters who were to terrorize such commercial crews as might attempt to navigate the river; he also told how light batteries might move swiftly along the banks and, at points commanding the channel, rain on the passing steamer unheralded destruction. He was silent upon the really serious matter, the patrol of the river by Federal gunboats which rendered commerce with the Trans-Mississippi all but impossible. This report, dated the 26th of November, gives a roseate view of the war in Tennessee and enlarges upon that dreadful battle of Chickamauga which "ranks as one of the grandest victories of the war." But even as the report was signed, Bragg was in full retreat after his great disaster at Chattanooga. On the 30th of November the Administration at Richmond received from him a dispatch that closed with these words: "I deem it due to the cause and to myself to ask for relief from command and an investigation into the causes of the defeat." In the middle of December, Joseph E. Johnston was appointed to succeed him. Whatever had been the illusions of the Government, they were now at an end. There was no denying that the war had entered a new stage and that the odds were grimly against the South. Davis recognized the gravity of the situation, and in his message to Congress in December, 1863, he admitted that the Trans-Mississippi was practically isolated. This was indeed a great catastrophe, for hereafter neither men nor supplies could be drawn from the far Southwest. Furthermore, the Confederacy had now lost its former precious advantage of using Mexico as a means of secret trade with Europe.