When Confederate President Jefferson Davis placed General Joseph Johnston in charge of the Army of Tennessee, Davis stated that the Southern interior lines made the West safe from Union intrusions. He made it clear to Johnston that all he had to do was move Rebel troops where they were needed in the West via their interior lines. Johnston disagreed with Davis' overly simplistic approach to the defense of the Western Theater. He reminded Davis that Tennessee was the key to the defense of the West. Its physical location was vital to the protection of Confederate depots in Chattanooga, Atlanta and other storehouses in the South. He also added that protecting the West was not as simple as Davis made it seem to appear. Shuttling Rebel forces from one location to another was sometimes difficult as the railroads seldom ran directly toward points the Southern army needed to reach on a timely basis. Even in the best of cases, Johnston said, travel was time consuming because of differing railroad gauges.