(CNN) -- 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."
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Samuel Moyn: WWI launched debate: can laws of war impose limits how war carried out?
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After WWI, aim was to end war, but in 100 years, aim shifted to making it more 'humane,' he says
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Moyn: Focus now not to end nations' aggression, but to stop atrocity. Vietnam a low point
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Since 9/11, our wars much cleaner, lawful; but WWI idea of 'war to end wars' failed, he says
For @placeholder, it may have been Vietnam that caused the transformation.
Consider the decision to target enemies to make sure only combatants rather than civilians are in our crosshairs: Vietnam was more like @placeholder, with lawyers nowhere to be found, and civilians dying in massive numbers.