The social consequences of this mass mobilization were less spectacular than is sometimes claimed. There were advances for the organized working class, especially its trade unions, especially in Britain, and arguably for women, but the working class of Europe paid a high price on the battlefield for social advances at home. In the defeated states there was very little social advance anyway.
The First World War redrew the map of Europe and the Middle East. Big empires such as the Ottoman Empire were defeated and collapsed, and were replaced by a number of weak successor states. Russia underwent a bloody civil war involving the overthrow of two Governments (the monarchy and the provisional government) before the establishment of a Communist Soviet Union which put it beyond European diplomacy for quite some time. Germany became a republic who expected defeat, and they were increasingly weakened by the burden of (arguably unfair) Allied reparations. France recovered the provinces of Alsace and Lorraine and received reparations, but continued to fear (maybe too strong a word?) the German province/empire that had once dominated them.
In terms of alliances and let downs, Italy was disappointed by the territorial rewards of its military sacrifice. This provided ground for Mussolini's Fascists to establish themselves within the Italian government, and they had overthrown parliamentary democracy by 1924. The British maintained the integrity and independence of Belgium. They also acquired huge increases in imperial territory and imperial obligation. But they did not achieve the security for themselves which they believed they would have.
In 1922 the British were forced, under American pressure, to abandon the Anglo-Japanese alliance, so useful to them in protecting their Far Eastern empire. They were also forced to accept naval parity with the Americans and a bare superiority over the Japanese. 'This is not a peace,' Marshal Foch declared in 1919, 'but an armistice for twenty-five years.'
The cost of all this in human terms was 8.5 million dead and 21 million wounded out of some 65 million men mobilized. Although this was huge, it was not the real impact. The real impact was moral. The losses struck a blow at European self-confidence and in their belief that they consisted of superior civilizations.
