In 1864, the prisoner exchange program had collapsed, a failure politically motivated by Abraham Lincoln's war council. Some victims of the program's failure were 600 Confederate officers from all 14 Southern states who were denied parole. In Charleston Harbor, 50 officers were held as human shields against the artillery fire of their comrades. Elsewhere, Confederate officers were forced to suffer through a winter during which they were deprived of medical care, food, and warmth. The soldiers slowly died from malnutrition, exposure, untreated wounds, and disease although food and medicine were available in abundance to their captors. Officers in charge of overseeing the prisoners were embarrassed by this treatment, but were forced to obey orders.