In the closing days of 1862, just three weeks before Emancipation, the administration of Abraham Lincoln commissioned a code setting forth the laws of war for US armies. It announced standards of conduct in wartime--concerning torture, prisoners of war, civilians, spies, and slaves--that shaped the course of the Civil War. By the twentieth century, Lincoln's code would be incorporated into the Geneva Conventions and form the basis of a new international law of war.

In this deeply original book, John Fabian Witt tells the fascinating history of the laws of war and its eminent cast of characters--Washington, Jefferson, Franklin, Madison, and Lincoln--as they crafted the articles that would change the course of world history. Witt's engrossing exploration of the dilemmas at the heart of the laws of war is a prehistory of our own era. Lincoln's Code reveals that the heated controversies of twenty-first-century warfare have roots going back to the beginnings of American history. It is a compelling story of ideals under pressure and a landmark contribution to our understanding of the American experience.