I find it amazing that after all that has been written about Sherman, little is discussed regarding the interior of Sherman’s spiritual life. Virtue and morality are deeply tied to ones belief , or lack thereof, in God and in ultimate reality. Sherman’s early life was disrupted by his fathers death and he ended up being raised in a foster home of committed Catholics at a time when Catholics were a small minority. His wife ( his foster sister) was pious, devout and prayerful. Sherman seemed to have wanted nothing to do with Christianity, Protestant or Catholic. So we can be sure the Christian moral ethics played small, if any part in his choices on his conduct of the war. The issue of faith was a constant tension between he and his wife in a marriage that was conflicted. Later, when his son decided to abandon law studies and become a Priest, Sherman basically went crackers. His reason was that he had expected his son to be a source of his future retirement funds. He all but disowned him for some length of time.
Unlike today Protestant Christianity saturated America in 1860. You could not escape it. Placing Sherman in the path of blood, suffering, and death on a daily basis, while not embracing the national civic religion one can see the interior tension Sherman might have been going through. How would his tensions have driven his choices on inflicting suffering? Then again, if he was cock sure there was no ultimate reality beyond this earth, or if he was essentially indifferent about God and faith, then his choices would have produced no internal conflict at all. I personally think the photos of Sherman reveal the face of a soul in deep interior pain.
He was not unmerciful and showed compassion many times. He and Grant seemed to share not only their Ohio roots, but an indifference to religion. Grant never seem to care and it created no real tension for him. I can’t prove this but I suspect Sherman was struggling with faith issues.
I agree that his decisions to destroy property that supported the war contributed to shoring the war. Truman decided to do worse but also ended the war and saved many lives.