As Johnston, Davis, and Seddon wrangled about command responsibilities, Southern chances of success in the Western Theater became increasingly dim. Grant had started to move, and in February 1863, Joe Johnston grew concerned about the Union canal-digging effort across the river from Vicksburg. Grant ultimately abandoned this, but not before Johnston had told the Confederate president that if Grant succeeded, moved his army south of Vicksburg, and then invested Port Hudson with the combined Union forces, “it would be difficult for us to succour the place. Indeed we have not the means of forming a relieving army.”

As spring came on, Johnston requested reinforcements from Virginia. Davis declined, there being insufficient troops. Davis, for his part, wanted to know if Johnston could strengthen Bragg’s army in Tennessee from units farther west. Johnston pronounced this difficult because “at Mobile, in Mississippi, and in Middle Tennessee we cannot foresee attack long enough beforehand to be able to re-enforce the threatened army from either of the others.” Moreover, the Confederates probably would not know about a Union attack on either of the first two until it actually happened. A Union push in middle Tennessee would give more warning, but only a few days—time enough to bring in reinforcements from eastern Tennessee but nowhere else. Johnston also pointed out the difficulty of temporarily shifting troops from Jackson, Mississippi, to Bragg’s army at Tullahoma, Tennessee, as Davis wanted. Transferring 8,000–10,000 troops would take three weeks, with an additional two weeks for their necessary wagons and horses.

Despite his lack of willingness to exercise his command, Johnston did understand the nature of the struggle in the West. “Our disadvantage in this warfare,” he told Davis, “is that the enemy can transfer an army from Mississippi to Nashville before we learn that it is in motion. While an equal body of our troops could not make the same movement (the corresponding one rather) in less than six weeks.” Lee, as we have seen, drew similar conclusions about Northern mobility. This put the lie to the contentions of Halleck and others in the North that the South held an inherent advantage because of its interior position. The Union’s ability to shift troops much more quickly via its superior railroads more than compensated for any geographical disadvantages. This also demonstrated the weakness in the arguments of Halleck and others that Lincoln did not understand theory. Intuitively, he grasped its shortcomings better than America’s Jomini expert.

In May, Johnston was promised reinforcements and ordered to Mississippi to take matters there in hand. “I shall go immediately, although unfit for field service,” he replied candidly and a little oddly. Grant, meanwhile, pushed south. In early April 1863, Halleck urged him to cooperate with Banks against Port Hudson should Banks not be able to reach Vicksburg. Grant, however, already had his course set. As mentioned previously, he planned to get south of Vicksburg and begin his campaign from New Carthage, Louisiana, roughly a dozen miles southwest of his target as the crow flies. He sent Halleck his plan, which was for part of the naval fleet to “run the batteries of Vicksburg” while he moved the army to either Warrenton or Grand Gulf, both on the Mississippi side of the river. Warrenton was approximately 7 miles south of Vicksburg and had good roads to the city. Grand Gulf, which also sat on the banks of the Mississippi, though a farther dozen or so air miles below, had a road leading to Jackson, Mississippi’s capital, and an important rail hub. “This is the only move I now see as practicable,” Grant wrote, “and hope it will meet your approval. I will keep my army together, and see to it that I am not cut off from my supplies, or beaten in any other way than in fair fight.” Grant’s staff and generals opposed the plan, particularly Sherman, who wrote his wife, Mary Ellen, that “though it is the plan it is not a good plan.” He also branded it “one of the most hazardous & desperate moves of this or any war.” Grant dismissed their fears and pushed along the campaign, demonstrating Clausewitz’s higher form of courage, meaning the fortitude to make a decision and then take responsibility for whatever transpires.