If there is no sign that the UN, for all its inadequacies, is about to collapse, it is not least because the postwar settlement of 1945 rested on a general recognition that international co-operation in all fields had to be stronger than it was under the League of Nations, the UN’s ill-fated predecessor. The destruction caused by the Second World War, with its 50 million or more dead, its ruined cities, its genocides, its widespread negation of civilised values, had a far more powerful effect than the deaths caused by the First World War, which were (with exceptions, notably the genocide of a million or more Armenian civilians, killed by the Turks in 1915) largely confined to troops on active service. In 1945, Hiroshima and Nagasaki provided an additional, ter­rible warning of what would happen if the world went to war again.

In 1914, by contrast, very few people had any idea of the cataclysm that was about to descend on them. Just as admirals thought that the war at sea would be a rerun of the great naval engagements of the past, so the generals thought the war on land would be something like the conflicts of the 1860s, opening with rapid, railway-borne advances to the front, followed by a decisive encounter in which the other side would meet with a shattering defeat; peace would then be concluded after a few weeks or at most a couple of months. Since those days, however, barbed wire, patented in 1874, and the machine-gun, perfected in portable form a decade later, had become standard defensive equipment; at the same time, the internal combustion engine and armour plating were not yet advanced enough to produce tanks that could overcome these obstacles effectively and restore movement to warfare. A few recognised these inconvenient facts, notably the Polish banker Jan Bloch, whose Modern Weapons and Modern War, published at the turn of the century, argued that in the next major war, “the spade will be as important as the rifle” and forecast that the war of the future would be a gridlock in which quick victory would be impossible.

But nobody heeded this prediction, because generals, politicians and civil servants were unable to accept its denial of easy victory. By 1910 at the latest, the idea that a war was coming was shared by many—indeed, generated a momentum towards it. Admiral Jackie Fisher wrote of the atmosphere he created in the Royal Navy after 1902: “We prepared for war in professional hours, talked war, thought war, and hoped for war.” The chief of the German general staff declared in 1912 that war must come “and the sooner the better!”. War in this vision appeared as something not only inevitable, but also positive. A German novelist wrote of August 1914: “At last life had regained an ideal significance. The great virtues of humanity ... fidelity, patriotism, readiness to die for an ideal ... were triumphing over the trading and shopkeeping spirit ... The war would cleanse mankind from all its impurities.” The war appeared as a chance to do something glorious in a prosaic age.

In like vein, British writers enthused about the opportunity that war would present: