At the beginning of the Civil War in 1861, few Americans had given much thought to the rules of engagement. Lincoln was no exception. When the cannonade started at Fort Sumter on April 12, 1861, Lincoln became a war president barely a month into his first term in office.
After the Confederate victories in the Shenandoah Valley during the spring of 1862 and the lack of any strategic attack during the early beginnings of the Peninsula Campaign, Lincoln traveled to the front lines to encourage more aggressive action by Gen. George McClellan’s Army of the Potomac. To win the war, Lincoln was beginning to think, the Union would have to attack the social fabric of the South. But McClellan resisted. He was one of the few Americans versed in the highly idealized rules of war handed down by the professional armies of 18th-century Europe.
Instead of embracing Lincoln’s new urgency, McClellan argued that a war among Christian and civilized people should not be a war against the people of the rebellious states, but a war between armies.
After appalling casualties on both sides at Antietam in September 1862, Lincoln commissioned a study to determine a new set of rules of war. These new rules were written by the Department of War and were led by a professor of political science at Columbia College named Francis Lieber. The code aimed to update the laws of war for ‘modern’ conditions while preventing aggressive ‘modern’ warfare from sliding into total destruction.
In early 1863, Lincoln’s new code reduced the international laws of war into a simple pamphlet for wide distribution to the generals, as well as amateur soldiers of the Union army. It prohibited torture, poisons, wanton destruction, and cruelty. It protected prisoners and forbade assassinations. It announced a sharp distinction between soldiers and noncombatants, and it forbade attacks motivated by revenge and the infliction of suffering for its own sake.
Most significantly, the code sought to protect channels of communication between warring armies. And it elevated the truce flag to a level of sacred honor. The code was given not just to the armies of the Union but to the armies of the Confederacy. The code set out the rules the Union would follow—and that the Union would expect the South to follow, too. For the next two years, prisoner-exchange negotiations relied on the code to set the rules for identifying those who were entitled to prisoner-of-war status.
In the decades after the Civil War, the Lieber Code (as it became known) would form the basis of the first Laws of War. Translations of the code spread through the armies of Prussia and France and into multinational treaties signed at The Hague. Following World War II, its provisions reappeared in the Geneva Conventions that are still in effect today.
This narrative is background for my next column regarding an incident that happened in 1864 that has a Portsmouth connection – a story about Union Private Allen VanKirk, captured while a flag of truce was being honored.