Throughout American history, policy toward prisoners of war has been improvised rather than carefully planned. The same held true during the Civil War. Although neither the Union nor the Confederacy prioritized the creation of an efficient prison system, prisoners of war became important tools that each side used to negotiate the major points of contention that developed during the war. The shared belief in the practice of retaliation led to an escalating cycle of mistreatment and contributed to the mental and physical misery of captives held by both sides. The suffering of prisoners did more to inhibit postwar reconciliation than any other episode of the war.

In the war’s early weeks, War Department officials in the Union and the Confederacy assumed that practices developed during the War of 1812 and the Mexican–American War would continue.