In terms of military tactics, General Sherman's "March to the Sea" was worthless. He engaged no armies, nor fought by what was then considered the Rules of Engagement. His whole objective in perpetuating a swath of destruction was to break the morale of the Confederacy. However, his scorched earth policy was not without precedent -- a year earlier, General Sheridan, coming upon the Shenandoah Valley, had been given orders to "eat out Virginia clear and clean . . . so that crows flying over it for the balance of this season will have to carry their provender with them." Destruction of this area caused food shortages in the South.
Warfare never remains contained between opposing armies. What happened during the Civil War was that it spread into the destruction of civilians and their holdings, who were supporting the Confederacy. Were Sherman's actions tactically necessary? No, but neither was the fire bombing of Dresden the Allies inflicted upon Germany -- the city had no strategic nor military value, but was destroyed because -- it could be destroyed.
How can measurement be made of the impact psychological warfare has in ending the real war?
One focal point of the debate over Sherman's "March to the Sea" is the fact that the destruction of the South was unreasonable. While Sherman's idea was to destroy the infrastructure and damage industry, there was also needless damage and destruction of personal property, and wanton theft. This concept of "total war" has been used by many countries, but for a general to inflict this upon his own countrymen was egregious, especially given the fact that Lincoln refused to allow the South to secede in order to preserve the nation and the economy of the United States. That is, why destroy a land that must be later rebuilt?
There is no doubt that the destruction of the South crippled it for decades, not to mention causing tremendous hatred for the North for the unwarranted cruelty. If Lincoln wanted to heal wounds, burning the South was not the way. (Ironically, nowadays the South with its automotive industries is economically better off than some states in the North. But, this situation is only a recent one.)
I think the previous post made strong points. I would like to add that the debate that might exist could be an example of historical analysis. At the point when Sherman made his progression through the South, there was much to indicate that the South, in its war with the North, was reaching its natural end. This is to say that the prolonged nature of the war, the lack of industrialization in the region, and the attrition over time had withered them as a viable opponent in the military conflict. The debate lies in whether Sherman needed to pursue such a strong policy of "scorched earth." Was it really needed to make the South endure such a brutal end? Others suggest that it was needed to "teach" the South a lesson. If there is a debate, it would be in whether or not Sherman's advance represented a strong close or an exercise in abuse of the South.
I'm sorry, but we can only answer one question at a time unless they're very closely related.
Sherman's march was not really debated. The North was happy with it because it helped them win the war. However, the South hated it and hated Sherman because of it.
The South saw the March as unnecessarily brutal. As his army marched through Georgia, Sherman had them destroy everything that he thought could be of use to the rebel army. This is in line with the idea of "total war," the idea that you don't just try to kill soldiers, but rather that you try to destroy their ability to fight.
Because of this, the army ripped up railroads, destroyed crops, killed animals and did other things like that which caused hardships for civilians. This is why the South hated it so much.