Story highlights Samuel Moyn: WWI launched debate: can laws of war impose limits how war carried out?

After WWI, aim was to end war, but in 100 years, aim shifted to making it more 'humane,' he says

Moyn: Focus now not to end nations' aggression, but to stop atrocity. Vietnam a low point

Since 9/11, our wars much cleaner, lawful; but WWI idea of 'war to end wars' failed, he says

The guns of August 1914 unleashed a debate that is still with us: Can the laws of war actually impose limits on how war is carried out?

Germany invaded Belgium, violating that nation's neutrality -- which was guaranteed by treaties stretching back to the 19th century. This act horrified the world -- as would the civilian occupation policies that marked German rule in Belgium, Northern France, and elsewhere during the long years of trench warfare.

The question of how much international law should be respected during wartime has resurfaced repeatedly through the 20th century -- in America, it has come up frequently since 9/11, especially surrounding the "torture debate."

Samuel Moyn

Indeed the revelations that American soldiers in Iraq brutalized detainees at Abu Ghraib prison marked a turning point in how Americans regarded the morality of "our" war, and on one level this was nothing new: atrocity has repeatedly stunned Americans throughout their history, and they have sometimes mobilized against it.

Yet on another level, the years since Abu Ghraib have marked a radical new stage, because of how central law has been to our debates about war: The American government tried to deny that treaties prohibiting torture (from the 1949 Geneva Conventions onward) applied to the global war on terror, but it failed. In fact, over the 20th century, the world took real strides towards the goal of "humanizing war," though perhaps only because the century also made war itself so much worse.

But there is another story about World War I and the legal consequences it set off that is less familiar and more disquieting. It is about a legacy we have lost, rather than one we have realized: that of aiming, through the laws of war, to bring war itself to an end.

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World War I, as Paul Fussell famously argued, discredited what Wilfred Owen in a classic poem called "the old lie": that it is sweet and honorable to die for one's country. But what it has meant to shift allegiances from nation to "humanity" has changed drastically over the 20th century among those flirting with wider and cosmopolitan sensibilities. Namely, the highest goal shifted from the abolition to the humanization of war.

When World War I ended, the German Kaiser was very nearly criminally tried. It was only his flight to the Netherlands that made him inaccessible to justice. But it was his aggression, rather than his army's atrocity, that mattered most. There is even evidence that after World War I the phrase "crimes against humanity" -- which now refers to abuses against civilians -- often meant warmongering itself.

In other words, the law would criminalize war, rather than merely make it cleaner. The Nuremberg trials after World War II maintained this focus, attending most to the Nazis' aggressive crimes against peace -- bringing war to the world like the Kaiser had before them -- than atrocities in general or crimes against humanity in particular.

By contrast, our post-9/11 debates around the laws of war have rarely centered on the moral validity or legal propriety of war itself . Rather, from the torture revealed at Abu Ghraib, to drones, and now surveillance, the concern of the mainstream of the American public has centered on how far the executive may go in the pursuit of victory. If law matters, it is to keep the war "humane," rather than to keep it from happening in the first place.

Photos: WWI surveillance Photos: WWI surveillance WWI surveillance – Air power harks back to Civil War-era hot air balloons and was used all over the theaters of World War I for reconnaissance, bombardment, and aerial combat. Here, the French-built Voisin "pusher," originally built for reconnaissance and later developed as a bomber. It is credited with the first air-to-air kill. Hide Caption 1 of 8 Photos: WWI surveillance WWI surveillance – British war photographer David McLellan, originator of the photographic section of the Royal Flying Corps, holds a camera specially adapted for aerial pictures in 1915. The potential of aerial surveillance and bombardment was most rigorously tested and developed in the British campaign against the Ottoman Empire during WWI. Hide Caption 2 of 8 Photos: WWI surveillance WWI surveillance – An aerial reconnaissance photograph from May 29, 1915, shows trench networks at Le Plantin, "Windy Corner," in France. Hide Caption 3 of 8 Photos: WWI surveillance WWI surveillance – An early aerial photograph from 1915 shows the Belgian town of Ypres, the site of three major battles during World War I, and almost completely devastated by bombing. Hide Caption 4 of 8 Photos: WWI surveillance WWI surveillance – A sergeant of the Royal Flying Corps demonstrates a C type aerial reconnaissance camera fixed to the fuselage of a BE2c aircraft, 1916. For the British, during the war and later for colonial policing in the postwar Middle East, surveillance aircraft seemed to promise vision beyond the mirages, sandstorms, and distances that made the region unmappable in their estimation. Hide Caption 5 of 8 Photos: WWI surveillance WWI surveillance – Surveillance was sometimes more low-tech, as in this German observation post in a tree during the Battle of Verdun, 1916 ... Hide Caption 6 of 8 Photos: WWI surveillance WWI surveillance – ... or this observation balloon, from which an American Army major commanded a view of the front lines in June 1918 ... Hide Caption 7 of 8 Photos: WWI surveillance WWI surveillance – ... and this not-very-subtle sausage-shaped observation balloon in France on November 10, 1918. The balloons were used for, among other things, artillery spotting. Because they were filled with flammable hydrogen, they were well-guarded by anti-aircraft artillery. Hide Caption 8 of 8

Photos: Photos: Women during World War I Photos: Photos: Women during World War I Women during World War I – Female army recruits from the United Kingdom are seen during drills in May 1917. World War I broke down barriers between military and civilian life. With the men away in battle, women took on an extraordinary role in support of the war, whether it was on the front lines or at home in factories and farms. Hide Caption 1 of 20 Photos: Photos: Women during World War I Women during World War I – Loretta Perfectus Walsh enlisted in the United States Naval Reserve in March 1917, becoming the first active-duty woman in the Navy and the first U.S. military woman who wasn't a nurse. Hide Caption 2 of 20 Photos: Photos: Women during World War I Women during World War I – Women work at the Gray & Davis Co. ordnance factory in Cambridge, Massachusetts. Munitions workers faced harsh working conditions that were sometimes lethal, such as in the Barnbow National Factory explosion that killed 35 near Leeds, England. Hide Caption 3 of 20 Photos: Photos: Women during World War I Women during World War I – A woman works as a porter at the Marylebone station in London. British propaganda posters declaring soldiers' dependence on female munitions workers gave women a sense that their labor contributions would be important -- and acknowledged. But this was not always the case. Hide Caption 4 of 20 Photos: Photos: Women during World War I Women during World War I – A Russian women's regiment from Petrograd (now St. Petersburg) relaxes in front of its tents. Women across the globe would serve directly on the battlefields, with many serving as nurses, ambulance drivers and cooks. Hide Caption 5 of 20 Photos: Photos: Women during World War I Women during World War I – Maria Bochkareva, nicknamed Yashka, was a Russian soldier who in 1917 created the 1st Russian Women's Battalion of Death -- an all-female combat unit. Hide Caption 6 of 20 Photos: Photos: Women during World War I Women during World War I – "Hello Girls" at work. The U.S. Army trained more than 400 female telephone operators to serve in France and England for the Army Signal Corps. These women were bilingual, speaking French and English. Hide Caption 7 of 20 Photos: Photos: Women during World War I Women during World War I – Grace Banker receives a Distinguished Medal of Service for her role as chief operator in the U.S. Army Signal Corps. She worked at a post close to the front lines in France. Hide Caption 8 of 20 Photos: Photos: Women during World War I Women during World War I – Female firefighters put a fire escape into position in the United Kingdom. Hide Caption 9 of 20 Photos: Photos: Women during World War I Women during World War I – Lenah Higbee, a Canadian-born U.S. Navy chief nurse, served as superintendent of the U.S. Navy Nurse Corps during World War I. She was the first female recipient of the Navy Cross. Hide Caption 10 of 20 Photos: Photos: Women during World War I Women during World War I – Nurses tend to wounded soldiers in France in 1915. Hide Caption 11 of 20 Photos: Photos: Women during World War I Women during World War I – Julia Stimson was superintendent of the U.S. Army Nurse Corps and the first woman to attain the rank of major in the Army. She earned the Distinguished Service Medal for her service in France. Hide Caption 12 of 20 Photos: Photos: Women during World War I Women during World War I – Mairi Chisholm and Elsie Knocker drive an ambulance in July 1917. The two British women ran a first-aid post in Belgium only 100 yards from the trenches. Hide Caption 13 of 20 Photos: Photos: Women during World War I Women during World War I – Milunka Savic was a Serbian combatant and the most decorated female fighter in the history of warfare. She was honored by multiple countries for her bravery. Hide Caption 14 of 20 Photos: Photos: Women during World War I Women during World War I – Mary Sophia Allen inspects policewomen in London in May 1915. Before the war, Allen had been imprisoned three times for her activism as a suffragette. She turned down an offer of wartime service with a Needlework Guild to become the second in command of the Women Police Service. Hide Caption 15 of 20 Photos: Photos: Women during World War I Women during World War I – A member of the Women's Forestry Corps, part of the Women's Land Army in the United Kingdom, works circa 1916. Hide Caption 16 of 20 Photos: Photos: Women during World War I Women during World War I – Women "navvies" work on railway building in Coventry, England. Hide Caption 17 of 20 Photos: Photos: Women during World War I Women during World War I – Dorothy Lawrence disguised herself as a man in order to become an English soldier in World War I. Hide Caption 18 of 20 Photos: Photos: Women during World War I Women during World War I – A female munitions worker welds at an armaments factory. Hide Caption 19 of 20 Photos: Photos: Women during World War I Women during World War I – A British Army lieutenant sits in a garden with his wife and three children while on leave during the war. In Great Britain and the United States, women confronted wartime shortages of food, fuel and housing as they struggled to maintain homes and families while they also worked outside the home. Hide Caption 20 of 20

Photos: Photos: Tribunals and justice after WWI Photos: Photos: Tribunals and justice after WWI Tribunals and justice after WWI – At Versailles Palace, representatives of Germany and the Allies sign the treaty that ended World War I, June 28, 1919. Article 231, the notorious War Guilt clause, required "Germany (to) accept the responsibility of Germany and her allies for causing all the loss and damage" during the war. Hide Caption 1 of 5 Photos: Photos: Tribunals and justice after WWI Tribunals and justice after WWI – At the Paris Peace Conference, held earlier in 1919, some 30 nations convened to reach the terms of peace, but it was "The Big Four" who would hold sway on Versailles' terms. Left to right: Italian Prime Minister Vittorio Orlando, British Prime Minister David Lloyd George, French Prime Minister Georges Clemenceau and U.S. President Woodrow Wilson. Hide Caption 2 of 5 Photos: Photos: Tribunals and justice after WWI Tribunals and justice after WWI – Versailles' collective punishment of a humiliated Germany is widely believed to have led to World War II, prompting a reorientation in international law: Guilty nations have been replaced by war criminals, prosecuted and punished by international tribunals. Here, German war crimes defendants sit in the Nuremberg courtroom of the International Tribunal after WWII. Hermann Goering, Rudolph Hess, Joachim Von Ribbentrop, Wilhelm Keitel (front row), and Karl Doenitz, Erich Raeder, Baldor von Schirach, Fritz Sauchel (second row). Hide Caption 3 of 5 Photos: Photos: Tribunals and justice after WWI Tribunals and justice after WWI – Nuon Chea, a former leader in the Khmer Rouge reign of terror and right hand man to Pol Pot, gets help to stand up in the dock before a hearing in 2008 at the U.N.-backed Cambodian war crimes court in Phnom Penh. A verdict is expected in August on Chea's indictment over atrocities. Hide Caption 4 of 5 Photos: Photos: Tribunals and justice after WWI Tribunals and justice after WWI – Former Yugoslav President Slobodan Milosevic enters the United Nations War Crimes Tribunal for the former Yugoslavia in The Hague in 2001. Milosevic was charged with war crimes, including genocide, and crimes against humanity in connection with the wars in Bosnia, Croatia, and Kosovo. His trial, which began in 2002, ended without a verdict when he was found dead in his prison cell in 2006. Hide Caption 5 of 5

Photos: Photos: WWI chemical weapons Photos: Photos: WWI chemical weapons Chemical weapons in World War I – World War I ushered in an era of chemical weapons use that lingers, lethally, into the present day. About 1 million casualties were inflicted, and 90,000 were killed. Here, French troops wear an early form of gas mask in the trenches during the first widespread use of gas, by the Germans at the Second Battle of Ypres in 1916. Hide Caption 1 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – French soldiers making a gas and flame attack on German trenches in Flanders, Belgium, in 1918. German forces were the first to open valves on gas cylinders, releasing the toxic cloud on unprepared French troops in Ypres in 1915. Hide Caption 2 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – The bodies of hundreds of Italian soldiers are strewn across the battlefield, victims of a gas and flame attack during World War I, as others haul the wounded on stretchers. They were members of the Ninth Italian Regiment of the Queen's Brigade. Hide Caption 3 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – Early gas masks were often ineffectual. The Germans and Americans would ultimately be the most successful in creating barriers to lethal gases. A German soldier shows how to wear one version. Hide Caption 4 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – A soldier demonstrates an ungainly French gas mask. "French masks were notoriously unreliable," wrote historian Gerald Fitzgerald. Hide Caption 5 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – A German cavalry unit with both horses and soldiers wearing gas masks advances during the Second Battle of the Aisne at Soissons, France, in June 1918. Hide Caption 6 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – A German soldier wears a more rudimentary gas mask in 1915. Although the Germans were first to deploy chemical weapons in the war, both sides were soon routinely using chlorine and other gases in battle. Hide Caption 7 of 8 Photos: Photos: WWI chemical weapons Chemical weapons in World War I – Men of the British Army's 55th Division, blinded by a poison gas attack, in April 1918. British soldier Wilfred Owen captured the panic of an attack in verse "Gas! Gas! Quick, boys! -- An ecstasy of fumbling, Fitting the clumsy helmets just in time; But someone still was yelling out and stumbling, And flound'ring like a man on fire or lime." Hide Caption 8 of 8

Photos: Photos of WWI's "Bionic Men" Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – The scale and type of physical injuries endured by soldiers injured in World War One challenged the ingenuity of prosthesis designers, whose work to replace lost body parts would let many return to productive civilian life, a process echoed today with soldiers injured in our recent wars. Here Austro-Hungarian soldiers practice walking with artificial legs at the First War Hospital, Budapest. See gallery showing the effects of the war. Hide Caption 1 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – German soldier with simple artificial legs, 1917. Hide Caption 2 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – Postcard of British soldiers using parallel bars to help them learn to walk with their artificial legs. Image was probably taken at Queen Mary's Convalescent Auxiliary Hospital, a specialized orthopedic hospital that opened in London in 1915. Hide Caption 3 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – A disabled German ex-serviceman works as a carpenter with the aid of a prosthetic arm, Germany, circa 1919. Hide Caption 4 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – Prosthesis for eye and eyelid, to attach to glasses, France, 1916. Hide Caption 5 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – Soldier wearing prothesis to replace one eye and the eyelids, France, 1916. Hide Caption 6 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – German soldier equipped with two, more sophisticated, artificial legs, 1917. Hide Caption 7 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – German man riding a bicycle using prostheses on both arms and legs. Photo by Dr. P. A. Smithe, American Red Cross surgeon at the Vienna Red Cross Hospital, 1914-1915. Hide Caption 8 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – An artificial limb maker at work in Berlin in 1919. Prosthetics were perhaps Berlin's busiest industry after the carnage of the Great War. Hide Caption 9 of 10 Photos: Photos of WWI's "Bionic Men" WWI's "Bionic Men" – Wounded veterans with their prostheses, 1916. Hide Caption 10 of 10

Many survivors of World War I would have viewed this as a drastic constriction of their aspirations and a failure of their aims. Even if it is justifiable, the narrowing of our concerns must be explained.

For Americans, it may have been Vietnam that caused the transformation. That era saw a massive spike in antiwar consciousness, and Americans joined the world in worrying that the country was now forsaking the very legacy of the laws of war it had helped build.

But after that generation's Abu Ghraib -- the My Lai massacre, whose revelation in army photographer Ron Haeberle's images was once equally famous -- a consensus slowly built. What people arguing about war could agree on was that it was immoral and illegal to fight it so brutally. The goal of criminalizing aggression lost traction, and focus on atrocity took its place.

In the years after Vietnam, more and more people signed on to this view. Barbara Keys shows it was after and in response to Vietnam that Americans joined the international human rights movement, which sponsored a Campaign against Torture, which in turn led to a treaty outlawing the practice, setting up the possibility for our torture debate.

Many of the statutes that most constrain the executive in the way it fights, such as the Foreign Intelligence Surveillance Act, were passed in this atmosphere. (Congress also passed laws trying to keep presidents from unilateral military action, especially the War Powers Resolution, but recent history shows it to be a dead letter.)

I find the Vietnam-era debate to be an illuminating point of comparison with our time. If we are honest, we will see that atrocities after America's 1965 escalation in Vietnam then dwarfed atrocities now. It hardly makes whatever violations we have committed excusable, of course, to say so.

The other day, President Barack Obama acknowledged that "the CIA tortured some folks" after 9/11, but the full documentation has remained a political football and neither Democrats nor Republicans want accountability for crimes.

But we should not let our justified outrage over these facts distract from the truth that America's post-9/11 military has fought some of the cleanest wars ever. In particular, compared with the crimes of prisoner detention and aerial targeting in Vietnam (and torture too), America's recent misdeeds have been minor.

One big reason is the U.S. military's own response to Vietnam: After decades of benign neglect or outright disregard, it started to treat the laws of war as real constraints on how it fights.

Consider the decision to target enemies to make sure only combatants rather than civilians are in our crosshairs: Vietnam was more like World War I, with lawyers nowhere to be found, and civilians dying in massive numbers. Today military and other government lawyers play a central role, as the recent controversy over the legal authorization of the drone strike on Anwar al-Awlaki attests.

The long trajectory from World War I has produced a paradoxical situation: We now have real, though insufficient, constraints on war's brutality, and more public discourse than ever about it. But we lack much concern about the goal of eliminating war itself. One legacy of the horrified response to modern war remains alive and well, but the other is forgotten. The "war to end all wars," as World War I has long been known, doesn't deserve that name yet.