Several factors appear to have contributed to the interwar prominence of the 'half-caste problem'. First, ideologies of race were perhaps most widely popularized and implemented by governments during these years — even though the intellectual bases of racial science were already under assault in Britain and the United States (Barkan 1992). Half-castes were significant because they affronted ideals of racial purity and challenged the real or imagined structures, including colonial structures, founded thereon.

Second, many colonial rulers were now keenly feeling the vulnerability of empire to moral objection and coloured revolt. As one former British Under-Secretary of State for the Colonies remarked, a wave of restlessness had swept the world since the Great War (Shiels 1933:321). In tropical possessions, wherever Europeans constituted managerial minorities, the question of where to place and how to treat the mixed-blood descendants of the ruling race was, in theory and practice, often problematic. Where the male half-caste was spurned by his father's people, they sometimes feared him as, metaphorically, a potential parricide. This spurning was painfully true of the British imperial tradition — though, as will be seen, there were exceptions, and the stereotypes which characterize French, Spanish, Portuguese, and Dutch colonialisms as more accepting of racial mixing do not entirely survive scrutiny.^[6] The half-caste woman was depicted as dangerous in a different way: she was tragically alluring, for in tempting a white man to marry she could bring him, it was often said, to social and racial ruin.^[7]

Third, half-castes were in effect metonyms for interracial sex. Male or female, they were its proof and product. If female, from a white man's viewpoint they were often seen to invite it. The accentuated sensitivity to racial divisions in these years therefore only served further to eroticize in the European imagination those who appeared to embody the sexual transgression of these divides. In societies of mass European settlement with indigenous minorities, such as Australia and New Zealand, the half-caste was perhaps not feared as such a potentially violent threat and was perhaps less eroticized. But here, too, 'the half-caste problem' was symbolically charged and complicated the process envisaged for shaping a national identity.^[8]