Four unprecedented upheavals created the first mass of permanently rightless people.

Evidence

The first World War exploded the European comity of nations beyond repair, something which no other war had ever done. Inflation destroyed the whole class of small property owners beyond hope for recovery or new formation, something which no monetary crisis had ever done so radically before. Unemployment, when it came, reached fabulous proportions, was no longer restricted to the working class but seized with insignificant exceptions whole nations. Civil wars which ushered in and spread over the twenty years of uneasy peace were not only bloodier and more cruel than all their predecessors; they were followed by migrations of groups who, unlike their happier predecessors in the religious wars, were welcomed nowhere and could be assimilated nowhere. Once they had left their homeland they remained homeless, once they had left their state they became stateless; once they had been deprived of their human rights they were rightless, the scum of the earth. — Hannah Arendt, The Origins of Totalitarianism, 667