Did they have authorization to practice what they considered retaliation or were they simply out of control? Senator Henderson of Kansas asked:
"Permit me to ask...under what authority the retaliation practiced by General Foster, of which he speaks, was adopted before Congress acted on the subject. If Congress has entire power over the question and Congress has not directed retaliation to be exercised, how could an officer in the field undertake to say that he would retaliate in the way ... stated? ... never would I consent to the slow system of destroying life by starvation or by cruelty in any form.
Source: Immortal Captives by Mauriel Phillips Joslyn (a detailed and thorough book)
I don't think Ms. Joslyn's book mentions that black Union POW's were made to work on rebel defensive works under fire well before the "immortal six hundred" took shape.
Walt