Just a little bit of history. The North and South actually did have prisoner exchanges where opposite forces sent prisoners back to their own armies to fight again.
According to Federal War Department statistics, 24,000 Union soldiers died of wounds, starvation and disease in Southern prisons during four long years of war. This was a tragic rate. But even more tragic was that 26,000 Confederate soldiers died in Union prisons during the same period. Many of the Confederate deaths were unnecessary, because the Union Army had a wealth of food and medical supplies that could have been made easily available to their Southern prisoners. But Union authorities maliciously refused to do so. After the dust of war had settled, the South, having held 50,000 more prisoners than the North, had 4,000 fewer inmate deaths
By 1864, Confederate soldiers were outnumbered three or even four to one, and by this time the Union, with more than enough men to use as replacement troops, adamantly refused to cooperate in prisoner exchanges. The Union blockade of Southern ports helped prevent the replenishment of critical medical supplies and other essentials. But the decision that was most detrimental to Union prisoners in Confederate prison pens was the decision on the part of the federal government to discontinue a prisoner-exchange program between the North and South.
Within a two-week period, Southern representatives paid two visits to the U.S. Secretary of War, Edwin Stanton, asking for prisoner exchanges. On the first visit, they offered to exchange prisoners of war man for man. On their second visit, the offer was to turn over all Union prisoners for all Confederate prisoners, even though the Confederacy held a great many more Union soldiers. And twice Stanton refused the Southern offer. The Confederates desperately thought of everything possible, up to kidnapping Lincoln and using him to force a prisoner exchange, to get their badly-needed manpower.
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thanx