>and this was put in as a sop to the former slave states. Citation please. While the prison population was much lower at the time they were being used as muni

>and this was put in as a sop to the former slave states. Citation please. While the prison population was much lower at the time they were being used as municipal labor. The "except prisoners" loophole was intended to grandfather in that system so as not to turn upside down the prison systems of all the states in the union at the time. Furthermore "a sop to the former slave states" was the last thing congress was doing at the time. They were far more interested in maximizing the legislate utility of time spent without having southern reps present to vote against northern interests. The threat of more states (MD, TN in particular) seceding was the line they were trying to walk up to but not cross. Edit: Is my analysis wrong or just inconvenient? I would be very interested in any source that can show that the northern states included the prison exemption in the 13A as a means to give the south a way to cling to some part of their slavery economy as opposed to a pragmatic "we'd rather not upset our prison systems, we already have a war and lots of unrest on our hands" exemption.