Why did the military strategy change during the civil war?

Answer 1

Because the wars fought until the fifties of the eighteenth century were largely based upon concepts, aims and technologies which were going back to the Napoleonic era. The armies were largely formed by professionals, the fronts were not extensive, there was no need to subject the opposing country, so that one or two decisive and costly defeats were generally sufficient to convince one of the belligerents to sue for peace giving in some territory and sacrificing or conceding some commercial and political advantages to the opponent. The Civil war was instead going to be an unprecedented kind of conflict. Soon after its outbreak, both sides became aware that it would have been a very long and costly one that had to be fought on immense fronts, involving practically the whole territory of the United States. Nothing to be compared with the relatively limited conflicts fought in Europe during the previous fifty years in terms of resources, men and means. In other words: the North had to subjugate the seceded states and conquest their whole vast territory; The South had to defeat the Union armies so decisively to determine the collapse of North's home front and their willingness to fight longer, thus managing to obtain the independence. That meant that a new military strategy, to substitute the one still in use in Europe, which proved to be but of little avail to reach the aforesaid goals, had to be adopted. The South, intensified its "defensive-offensive" attitude, thus implementing the effectiveness of the "delaying strategy" adopted after the early stage of the war. The Confederates exploited very well the geographical features of their territory, being often able to take advantage of their opponent's mistakes to frustrate their offensives and mount devastating counteroffensives, which, though insufficient to win the war, were perfectly in line with their objective. Indeed, due to the inferiority in men and resources, they did their best thanks to the competence of most of their military leaders. What they were missing, was a skilled General in Chief, who were able to effectively coordinate the activities of all fronts, since Jefferson Davis, the Commander in Chief, stubbornly avoided to appoint one, believing himself competent enough to hold also this commission. Indeed they had one: the ingenious Lee, but he was appointed too late to that rank to affect the outcome of the war. The very real change of strategy was realized on the side of the Union, after the appointment of Grant to General in Chief on March 9,1863. In full accordance with Lincoln he deeply reorganized the chain of command of the Union Army, and created an effective General Staff, appointing Gen. Halleck to Chief of Staff. All more or less independent Command, with exception of that of Gen. Banks, who was maintained only for political reasons, were eliminated thus providing that all Union Armies in the field had to be submitted to the order emanated by the General Staff. He then set up and put in motion a Grand Strategy, whose basic principles were: 1 - all armies had to operate, as far as possible, at the unison, in order to avoid that the enemy could reinforce one or other sector by means of displacement of troops by internal lines. 2 - The main task of all armies was that to engage and destroy the enemy armies, irrespective of how important a secondary objective would be. 3 - The exchange of prisoners was no more admitted. 4 - Grant, who had elected his Headquarters by the Army of Potomac applying those concepts and using the strategic intimidation by menacing Richmond succeeded in making Lee pinned down to his initiative, his endless pressure and deprived of his freedom of movement, until the Confederate general was forced to fight within about thirty kilometers from the Capital of the Confederacy. 5 - Starting from Sherman's capture of Atlanta, followed by the so called March to the Sea it was decided that the warfare had to be escalated up to the point it became a "Total War". That meant that operating armies had to live off the land, regardless to the needs or the damages caused to the civilians. All military and civilians infrastructures, crops and other sources of supply existing on the concerned territory had to be destroyed to weaken and break down the enemy's morale and stamina of their armies and their Home Front. This new "Grand Strategy" was pivotal to reach the goal of winning the war within a reasonable period of time. Of course Grant was able to carry out successfully his strategy also thanks to the great resources at his disposal. Anyhow it's worth remembering that those resources existed also when McClellan was General in Chief and was supported by the whole Union, but he was not up to the task and the Union top military leaders of those years neither.