Even while "the monstrous anger of the guns" was hauling millions to their death, the blame game was already well under way.
In one corner, the Germans were branded as aggressors, while elsewhere Serbia, Russia and various combinations of nations were held culpable in some way.
The gargantuan scale and grisly nature of the carnage demanded responsibility in measure with the rapidly piling body count. And with a few notable exceptions, the need to hold a nation or an ethnic group accountable has persisted to the present day.
The compulsion to blame has all the logic of a straightforward scientific formula: roughly 16 million people were killed in the conflict, and so it follows that an aggressor was behind this calamity and ought to be identified. Otherwise, that dreaded question lurks: "How could it happen if no one was responsible?"
Of course, most historians now give a more nuanced account of the events leading up to the war, and allocate portions of the blame among several participants.
Yet, here we are, a century after the outbreak of the war, and still no definitive verdict on the ultimate responsibility has emerged - perhaps rightly so.
Unlike World War II, where German (and never forget Austrian) culpability is clear and absolute, responsibility for the Great War is still mired in intractable debate.
If you are the sort of person who cannot accept the principle of no ultimate blame, then one place to search for answers for how the war started and spread is the system of international entanglements which dragged one country after another into a conflict often of only peripheral importance to their national security.
Maybe in another century, historians will scratch their heads in bewilderment that New Zealanders responded to a call to fight at the opposite end of the world, in hellish conditions, for a murky cause, when there seemed no immediate threat to the country's interests. How could stubborn patriotism, they might ask, ever justify the death of 18,000 New Zealanders?
Ironically, though, the same patchwork of alliances which led to this global conflagration aimed at achieving precisely the opposite.
The various international treaties and agreements, many a hangover from the era of 19th century diplomacy, were designed to bring greater regional stability and ensure a balance of power that would deter any party from attacking another.
And for years it worked. Of course, it was based on the fear that the other bloc was a potential aggressor, and so you needed constantly to shore up your own position. However, as history repeatedly reminds us, arms races and a desire for peace are not always the happy couple they pretend to be.
Another important object of blame is the nasty form of nationalism that flared among so many European countries from the end of the 19th century. There are other ingredients that can be added to the mix: the waning of some superpowers; unresolved regional tensions in various parts of the world; the arbitrary rearranging of national boundaries; the feeling by some smaller nations that they had been victims of superpower politicking; and economies teetering on the brink of collapse.
Perhaps the root cause for World War I, like practically ever other conflict in history, lies closer to home, with our innate propensity for aggression.
As the military strategist Carl von Clausewitz, himself no shrinking pacifist, reluctantly conceded, people and nations have a capacity for "the passion of hatred of the wildest description".
The storms of war between countries are maintained by the gusts of popular animus. Without at least some public backing, wars are difficult to prosecute. With communities fully mobilised behind a belligerent cause, the possibilities, as World War I forcefully reminds us, are hellish.
Dr Paul Moon is professor of history at AUT University.