Francis Lieber, circa 1865. Credit: Library of Congress.

American military and political leaders since the Revolutionary War have grappled with the problem of whether conduct in the hellish horror and chaos of war can be regulated by law.

Before the Civil War, American troops relied largely on Enlightenment customs of war that grew out of European conflicts, although rules were flexible or ignored depending on the particular commanders, whether military concerns outweighed the niceties of “civilized” war, and the character of the enemy -- whether an organized national military or a band of Indians or Mexican guerilla fighters.

In late 1862, after a year and a half of bloody fighting in the Civil War, Union General-in-Chief Henry Halleck and Secretary of War Edwin Stanton called for a code of the laws of war for the Union military as President Abraham Lincoln embarked on radical new strategy of all-out war against the Confederacy that extinguished any hope of compromise peace. The core of that strategy was the Emancipation Proclamation, a revolutionary use of federal power that freed slaves in enemy territory and led to Union recruiting of black soldiers.

Union leaders tapped Francis Lieber, a law professor and Prussian immigrant, to draft the laws of war. Lieber’s code provided guidance on civilized conduct in cases of torture and treatment prisoners of war, slaves, and spies, and other matters. The code prohibited cruelty but did not constrain an all-out war in the name of a just cause. Lieber agreed with General William T. Sherman’s sentiment that unsparing but short wars are the most humane, as embodied in section 29 of the Lieber Code: “The more vigorously wars are pursued, the better it is for humanity. Sharp wars are brief.”

The code was approved by Lincoln and governed the conduct of the Union military in the last two years of the bloody conflict. And the code condoned emancipation as well as Sherman’s devastating March to the Sea through the cities of the South.

“Lincoln’s Code” survived the American Civil War to become the basis for international laws of war as European powers adopted the rules and the Geneva Conventions embraced and expanded the rules, and the U.S. troops followed the code through two world wars.

Law professor and historian Dr. John Fabian Witt recounts the story behind Lieber’s work for Lincoln and traces the history of the American struggle with the rules and customs of war from the time of the founders in his groundbreaking new book Lincoln’s Code: The Laws of War in American History (Free Press). Dr. Witt pays special attention to how the issue of slavery haunted decisions on any rules adopted by the United States from the time of the Revolution. He also explores the elusive moral and legal complexities that leaders agonized over in shaping the laws of war.

Dr. Witt has been praised for his lively writing and deft interweaving of history, law and original analysis. For example, Harvard law professor Charles Fried wrote of Lincoln’s Code: “A gripping narrative of the struggle to maintain the aspiration to honor, decency and common humanity amidst the brutal imperatives of war -- from our war for independence, through the Civil War to the suppression of the insurrection in the Philippines. At the center John Witt places the first code for the conduct of war, promulgated by Lincoln during the darkest days of the Civil War: harsh, relentless, realistic, yet placing firm limits forbidding torture, the abuse of prisoners, treachery and purposeful harm to civilians. This book is an important addition to the ever-growing monument to our greatest and most complex national leader.” And Gary J. Bass commented in The New York Times Book Review: “Lincoln’s Code is both a celebratory chronicle of American lawmaking and a gruesome record of American wartime cruelty ... This monumental book, resting on colossal archival research and packed with memorable stories and arguments, is a major contribution ...”

Dr. Witt is Allen H. Duffy Class of 1960 Professor of Law at Yale Law School, a Professor of History in the Yale History Department, and a Guggenheim Foundation Fellow. His other books include Patriots and Cosmopolitans: Hidden Histories of American Law, and the prizewinning The Accidental Republic: Crippled Workingmen, Destitute Widows, and the Remaking of American Law. His writing has also appeared in numerous academic journals such as the American Historical Review, the Columbia Law Review, the Harvard Law Review, and the Yale Law Journal, as well as in The New York Times, Slate, and The Washington Post. Professor Witt is a graduate of Yale Law School and Yale College and he holds a Ph.D. in history from Yale. Before returning to Yale, he was the George Welwood Murray Professor of Legal History at Columbia University.

Dr. Witt spoke about his book recently by telephone from his office at Yale University in Connecticut.

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What sparked your interest in the law of war?

Dr. John Fabian Witt: A couple years after 9/11, two stories circulated in the culture about the laws of war in the United States, and they were at odds with one another. One was that international law was a new imposition that hadn’t been there before -- and it was Europeans telling Americans what to do. The second one was that we’d been following these rules faithfully since the founding fathers.

I was struck that both of these narratives existed in the culture and that there was very little literature to help us get a grip on which one was right. It seemed like an opportunity to me. I thought I’d go into the materials and figure out which of these two stories is correct, and I found that neither one was correct. They were both wrong and the story is much more interesting than most people expected.

Since 9/11, we’ve been using military commissions, torture and drone attacks that often kill innocent civilians, and some of our civilian and military leaders claim these questionable tactics are required in the name of military necessity. Your book suggests that, even back to the Revolutionary War, military necessity has trumped all other factors in observing any laws of war.

Military necessity is a powerful idea, and Lieber and Lincoln engaged with that tradition in their own way: Lieber in drafting the code and Lincoln in the Emancipation Proclamation, which he rooted expressly in military necessity.

It’s an all-purpose, one-size-fits-all warrant for answering difficult questions and empowering powerful armies to do what needs to be done to accomplish their ends. It also has a limit built into it, which prohibits irrational wanton behavior that is not instrumentally linked to accomplishing the legitimate end in view. You can understand why a powerful state would want that military necessity standard because it empowers [the state] to accomplish what it wants to accomplish.

What I say is that every generation of American leaders and soldiers has confronted its own law of war crisis. We often tell ourselves that we’re dealing with novel problems that are created by things like drones and enhanced interrogation that require a departure from the longstanding rules. The idea that there’s been a body of longstanding rules that weren’t themselves innovations and departures from what had gone before them is false.

The story is one of debates, furious controversy, and excruciatingly difficult situations going all the way back to the founding and before. Each generation has revived the rules, updated them and transformed them, sometimes to serve their interests no doubt. I think the fact that the conversation has gone on for so long shows that the laws of war are not entirely changeable to serve the needs of the moment. They exert some gravitational force and have so on every generation.

You vividly describe the ferocious fighting in the closing years of the Revolutionary War. Some readers may be surprised by the brutality on both sides as well as Thomas Jefferson’s call for a merciless, devastating war while Washington tried to fight a more restrained war in observance of the rules of war embraced by European nations.

Beginning in 1779 or so, the war went south in two ways. It moved to the southern Atlantic coast and it became a much more internecine, terrible conflict; one that was fought between Loyalist and Patriot militias in ways that featured shocking brutality on both sides. Jefferson saw that southern conflict first hand.

The southern conflict happened within a large slave population, and that became one of the central themes that animates the whole book -- the story of slavery from 1775 through the Civil War.

Washington is an interesting place to start. He seems to make the rules of war one of the centerpieces of American strategy. He does that partly because that’s the identity of a civilized soldier in the late eighteenth century -- to take those rules seriously -- but partly it’s in the American interest to do so, because the position of the United States was that they’ve declared themselves an independent state on the international scene and thus entitled to the privileges and obligations of these rules.

The position of Great Britain was that these upstart colonies were no such thing. They’re places in which a group of criminal rebels have conspired to illegally throw off their rightful sovereign.

To say that the laws of war apply and that we’ll follow them is an assertion of great interest to Washington and the Continental Congress from 1775 onward.

After the Revolution, it seems that the rules of war were flexible or didn’t apply in conflicts with the Indians and in the Mexican War.

I had a great time writing about the Indians. Indian warfare, it turns out, was a practice of conflict that had its own internal, ritualized rule structure. European colonists and later Americans in the early Republic thought of Indian warfare as unrestrained violence replete with torture and sometimes ritualized cannibalism and the like.

It turns out that Indian and European warfare each had their own distinctive rule systems, but they weren’t rule systems that were intelligible to the other point of view. Each side seems to have thought of the other’s way of war as a lawless way of war that knew no limits. Indians would look to the European practice and see mass destruction and be shocked. Likewise, Europeans would look to the Indian ways of war and see torture and be horrified. It led to a vicious race to the bottom that produced some of the nightmarish Indian conflicts that we know of.

There was a possibility that the Indian mechanisms for containing the savagery of warfare may have been more effective than most European analogs. They often involved singling out a single captured enemy warrior and ritually torturing and executing this man, often with the effect of limiting the scope of the violence to other members of the enemy tribe. It looks horrific to the European point of view. In some ways, many male warriors in victim-prisoner situations experienced a vindication of their warrior identity by withstanding as long as possible this kind of treatment. In some ways it was a different symbolic economy, but one that on its own terms functioned well although horrific from another point of view.

Also, after the Revolution, there was a great concern about the law of war at sea, and Benjamin Franklin was very involved in crafting maritime rules on blockades and privateering and related issues.

Franklin’s an interesting character here. The language of the laws of armed conflict was a trans-Atlantic language of the elite of the late eighteenth century, and Franklin was a celebrity figure of that elite culture and championed an approach to the rules of warfare that would have limited the domain of war and kept it away from the commercial activity that he prized so highly. He would have kept it away from all the peaceful commerce. This was a gloriously humane vision. On the other hand, it served the interests of a small, commercial republic that had no fighting force of its own.

In the Mexican War, a great concern arose about how to deal with guerilla fighters.

Yes. That conflict pitted American volunteers, often barely trained at all, against Mexican irregular forces that were commissioned by the Mexican government, but fought irregularly. After the first year of the war, the Mexican army in pitched battles did incredibly poorly, and so the Mexican strategy was to fall back on a guerilla campaign. This produced a real set of questions about whether guerillas were entitled to the same privileges as regular, uniformed soldiers -- and helped produce the military commissions we have at Guantanamo today.

The Lieber Code -- or Lincoln Code -- is the centerpiece of your book. What was the situation of Lincoln and Confederate President Jefferson Davis at the outbreak of the Civil War on application of the law of war -- and whether to treat the enemy troops as soldiers or criminals?

Lincoln found himself in the role of King George III, which was a point that Jefferson Davis and company took great delight in pointing out. It’s one of the reasons why the Confederacy was quite conservative in its law of war project, by which I mean that its approach to the law of war is consistent with American tradition going back to the Revolution. It doesn’t have a need to innovate. It just wants to defend the existing laws of war, to invoke them on behalf of the Confederacy, and to establish that the Confederacy is entitled to their protections and obligations.

The Union, on the other hand, has an excruciatingly more difficult choice: to decide whether the law of war is relevant at all. Then, as the second year of the war gets under way, and the failures of the first year become clear and that excruciating choice becomes even more difficult because the Union has decided two things: to step up the aggressiveness of the war effort, which raised real questions about humanitarian obligations in wartime, and second it raised the question of emancipation. Since 1775, American soldiers and statesmen announced again and again that emancipating any slaves was an uncivilized act of warfare that no civilized army could lawfully engage in.

The real challenge in late 1862 as emancipation is pending is to figure out how to make the law of war tradition in the United States consistent with the Union’s posture on emancipation and the war strategy.

You outline how slavery and emancipation shaped the American law of war.

The modern laws of war we have today are really a legacy of the American emancipation experience. That’s not a story I planned to tell, and not one I guessed I would be telling when I thought of this book.

Lincoln is a brilliant just war theorist. In August and September 1862, before he makes emancipation public, he had long deliberations where he reflected on the fact that he and hundreds of thousands of Union soldiers were convinced of the righteousness of their cause. On the other hand, there are hundreds of thousands of Confederate soldiers who are just as convinced of the righteousness of their cause.

That’s the fundamental tenet of the laws of war: that both sides are convinced that they’re right, and in those cases some kind of moral modesty is required. If we can get each side to suspend its conviction of self-righteousness for just the purpose of regulating war, we might be able to get a more humane conflict. You don’t execute the prisoner because you think he’s a criminal. Be modest about the righteousness of your side. That’s the fundamental premise of the laws of war.

But Lincoln makes a further observation, and this is where he’s pioneering. There’s a flaw here. Lincoln says to himself, I’ve already committed these men to battle. Tens of thousands of these men have already died by August of 1862. I have to be committed to the righteousness of my side. Otherwise I have no account of why I’m here in the first place. And so that led him a view that there were two imperatives. One was to act forcefully when more forceful action was morally required but, two, to act with modesty because one could never be sure that one was fighting on the side of righteousness. So he said we no longer live in the age of miracles. I can’t be sure that there will be a divine revelation that will reveal which of these two sides is right.

Then, after [the Union victory at] Antietam, he decided that Antietam was the miracle or revelation -- the only kind of grim miracle the modern world recognized that allows Lincoln to go forward publically with the emancipation policy.

And Frances Lieber comes into the story after Antietam when he’s called on by the Lincoln Administration to draft rules of war.

Dr. John Fabian Witt: Yes. This is one of the great forgotten characters of American history. He’s an enthusiastic, sometimes garrulous participant in the public intellectual culture of antebellum America.

He was a Prussian immigrant who left reactionary, post-Napoleonic Europe because he was too liberal for the conservative political climate of the times and got in trouble with the Prussian authorities. He travelled first to Greece and fought for Greek independence against the Turks with Lord Byron and the Romantic enthusiasts for Greek independence. Then he spent time in England and eventually came to the United States.

He couldn’t get a job at a northern university. He spent some time in Boston and Philadelphia and New York. Eventually, he ends up in South Carolina where he spent two decades on the little faculty of the College of South Carolina -- now the University of South Carolina in Columbia. He experiences himself in a backwater in those twenty years, rightly or wrongly, but far away from the intellectual elite in the Northwest on the Atlantic seaboard.

He eventually made his way to Columbia College in 1856. On the eve of the war, he was a man with connections both North and South. He was trained in war with experiences as a veteran in European warfare. So he has this strange experience and sons fighting for North and South. He’s always been against slavery, but in South Carolina, he owned slaves who worked as domestics. He was in this extraordinary position to craft a set of rules to govern a conflict between these two sections of the country.

In the winter of 1861-62, he gives a set of lectures [on laws of war] at Columbia Law School. Not that much had happened when he started lecturing in October 1861. There had been the first battle of Bull Run, but not too much else.

That winter, every student at the Columbia Law School enrolled in his lectures and there were reporters in the audience. The New York Times covered them. They’re of great interest in a country that doesn’t know much about these rules, but for which these rules are suddenly of considerable public moment.

Because those lectures are reprinted in the Times, they bring him to the attention of American military leaders, some of whom had known him for many years as a public intellectual, especially Henry Halleck who, in the fall of 1862, became general-in-chief of the Union army.

How did Lieber come to Lincoln’s attention?

He was a prolific and active correspondent with Halleck, Attorney General Edward Bates, and Secretary of War Edwin Stanton. He meets Lincoln on several occasions during the first two years of the war. He’s even a figure in the extended circle of the Lincoln administration from the very beginning of Lincoln’s presidency.

He got back in personal touch with Halleck because his second son, Hamilton Lieber, was badly wounded at Fort Donelson and lost his right arm. Lieber, like many Civil War fathers, raced across the country to help his son. Civil War battlefield medicine being what it was, fathers tried to get their sons out of there as fast as possible. In the course of looking for Hamilton -- there are no centralized records of where these wounded men are sent -- he finds his way to Halleck to identify where his son was. In 1862, with emancipation on the way, Halleck as general-in-chief realized he must transform the law of war tradition, and Lieber is the first person he calls on.

And you describe in detail Lieber’s work on these new rules. Weren’t they issued in the spring of 1863?

The date on them is April 24, 1863, but I can’t find any evidence that anyone knew much about them until the middle of May 1863. Some parts of them were issued earlier -- parts that were most pressing but less controversial. The most controversial parts were on slave organizations. There were rules in there ranging from torture to poison to prisoners of war to military necessity and prescribed prisoner paroles and prisoner exchanges. But the most important rules and most original rules that make the document distinctive in the law of war tradition were on slavery and black soldiers.

There were more rules on slavery and black soldiers in the code than on any other subject such as torture or prisoners of war. What called forth the code was the need to overturn the longstanding American tradition of resistance to the idea of emancipation in wartime and to deal with the problem of the Southern reaction to the arming of black soldiers.

Jefferson Davis and the Confederate leadership announce early on that black soldiers, even in Union uniform, will be treated as slaves engaged in uprising or as men trying to instigate a slave uprising. They’ll be treated as criminals subject to the criminal laws of Southern states, and not treated as soldiers. Eventually, they’ll be executed or re-enslaved instead of imprisoned on the same terms as white soldiers.

By late 1862 and early 1863, this is a real problem for the Lincoln administration. The [Union] turned decisively toward recruiting free blacks in the North and hoped to recruit former slaves in the South. By the end of the war, more than 200,000 blacks participated in the Union armed forces. For the Lincoln administration to recruit them, they were promised a commitment to have them treated as soldiers and not just as wanton criminals.

And you recount the horrific response of the Confederacy with re-enslavement and massacres of black soldiers, such as the massacre by Nathan Bedford Forrest’s troop of more than 200 captured black soldiers at Fort Pillow.

The Fort Pillow massacre turned out to be just one of the most famous examples of a widespread Confederate policy. The policy of summary execution was never officially approved at the top of the Confederate leadership, but it was much talked about. It appears that some Confederate officers adopted a policy of summary execution because public trials and executions would tempt Union retaliation, but simple execution away from public scrutiny could be done in ways that might not produce retaliation because the Union would never know.

Readers may be surprised that Lieber believed that “short, sharp wars” -- more devastating wars -- were more humane in the long run than wars where the military conformed to rules to make war more civil.

Yes. Lieber is both the creator of the modern law of war tradition and one of its toughest critics. The laws of war he creates that Lincoln issues as an order are laws of war that have humanitarian restraints, but also license and warrant terrible violence. One of the central things I wanted to bring out in the book was the ambiguity and ambivalences in this fraught legal tradition.

Sherman’s March to the Sea captures the real ambivalences of the laws of war that run through the nineteenth century, especially among a generation of people who couldn’t imagine the fire bombing of Dresden and Tokyo, and atomic weapons at Hiroshima and Nagasaki -- that there was a real logic to this “short and sharp” conflict as the more humane conflict. It’s the same logic that Curtis Lemay and Henry Stimson adopt in Japan in the summer of 1945.

Didn’t Sherman’s relentless campaign in the South, as some argue, show that military necessity trumped any restraints imposed by Lieber’s laws of war?

Historians have paid little attention to Lieber and this text. It’s interesting to puzzle out why. My impression is that historians, thinking that the laws of war must be a body of humanitarian limits, have looked at the conflict as it was fought and concluded that it cannot be that the laws of war played much of a role in this conflict. This is a war that some historians -- and I think wrongly -- call a “total war,” the forerunner of the horrific conflicts in the world wars of the twentieth century.

This conclusion, that the laws of war have been a sideshow, is a misunderstanding of what the laws of war do. They legitimate conflict as much as they try to restrain it. They are a vehicle for establishing some limited cooperation between enemies. They were vehicles for signaling internationally to other nations, like Britain and France that were key audiences for the Lincoln administration for all of its international law and law of war.

If we look more closely, we can see that the law of war is saturated by the black prisoner of war problem. It powerfully shaped the military commissions. There were more than four thousand military commissions during the course of the war. As many as a thousand of them, by my count, were law of war military commissions charging law of war violations. And the Lieber text and the law of war tradition were the blueprint for those military commissions.

The laws of war aren’t contradicted so much by Sherman’s March so much as they culminated in Sherman’s March. That’s the terrible ambiguity of the laws of war. It’s not a story about laws of war being irrelevant. To the contrary, it’s a story about the complicated social function of the rules.

You write of two trends now with the laws of war: a humanitarian trend and a war crimes trend. Did the Lieber code affect Henri Dunant’s humanitarian rules he set out in the Geneva Convention of 1864?

These are parallel tracks. Dunant in Switzerland created a set of rules for the sick and wounded on the field. Lieber’s rules are more ambitious. The sick and wounded on the field are the low-hanging fruit for humanitarians. There’s not much of a stake that any army in the world has in the people who are no longer available to fight.

Lieber’s rules are not adopted into an international convention until thirty-five years later, at the Hague in 1899. When they are adopted, it’s a treaty that the United States signs onto with all of the states of Europe. It’s a treaty powerfully modeled on the rules Lincoln issued in 1863.

There’s a great irony in the American observance of the rules during the Philippine insurrection as Edwin Glenn commanded troops who tortured insurgents and, a few years later, wrote the rules that American troops would be instructed to follow in both world wars.

Glenn embodies the hypocrisy of this law of war tradition. He was a self-acknowledged torture expert and led the American tactical torture team in the Philippines conflict. But when it comes time for him to produce the update of the Lieber Code -- the update that will follow American soldiers across the Atlantic twice in the first half of the twentieth century -- [Glenn] writes a code with rules that squarely make illegal what he did in the Philippines and they have a hopeful humanitarian dimension along with the inevitable fierce violence that they legitimate.

This is another story, among many you tell, that I had never heard about before.

Your audience may be interested that this field -- the laws of war in American history and international history -- is ripe for a lot of writing. I hope that my book is just the first in a series that will come.

Would you like to say anything else about the legacy of the Lieber Code -- Lincoln’s Code -- and how it guides us now?

The laws of war rarely if ever have delivered crisp answers that tell us what to do in crisis situations, but they’ve created a conversational frame that has allowed us to keep ourselves in touch with our ideals and cooperate with our friends and sometimes even our enemies in grave times of national crisis. That’s been their limit and that’s been their values across more than two centuries of American history.

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