So the truth of the matter probably is that in the infinite, complicated economy of the Civil War it was better to keep Ben Butler a major general, even though soldiers were needlessly killed because of it, than it was to inject him back into the political whirlpool. Washington saw it so, at any rate, and Washington had to balance fearful intangibles when it made its decision. And although there was not, fortunately, anyone else quite like Butler, there were many other cases where similar intangibles had to be balanced- cases where the Administration had to ask, in effect: Where will this man do the least harm- as a general, or as a politician out of control. Often enough the wrong guess was made, but that was the kind of riddle the times were asking.
Halleck understood these matters, and when Grant first began suggesting that it would be easier to win the war with Butler a civilian, Halleck tried to explain to him that political considerations must at times override even the professional judgment of the general in chief. A little earlier, Halleck had frankly confessed in a letter to Sherman that "it seems little better than murder to give important commands to such men a Banks, Butler, McClernand, Sigel and Lew Wallace, and yet it seems impossible to prevent it." Halleck was right. It was impossible to prevent it. The trouble was that the army had to carry these costly misfits on its shoulders.
From A Stillness at Appomattox, page 210
Halleck understood these matters, and when Grant first began suggesting that it would be easier to win the war with Butler a civilian, Halleck tried to explain to him that political considerations must at times override even the professional judgment of the general in chief. A little earlier, Halleck had frankly confessed in a letter to Sherman that "it seems little better than murder to give important commands to such men a Banks, Butler, McClernand, Sigel and Lew Wallace, and yet it seems impossible to prevent it." Halleck was right. It was impossible to prevent it. The trouble was that the army had to carry these costly misfits on its shoulders.
From A Stillness at Appomattox, page 210