Ngô Đình Nhu was a Vietnamese archivist and politician. He was the younger brother and chief political advisor of South Vietnam's first president, Ngô Đình Diệm. Although he held no formal executive position, he wielded immense unofficial power, exercising personal command of both the ARVN Special Forces and the Cần Lao political apparatus which served as the regime's de facto secret police.
In his early age, Nhu was a quiet and bookish individual who showed little inclination towards the political path taken by his elder brothers. While training as an archivist in France, Nhu adopted the Roman Catholic ideology of personalism, although critics claimed that he misused that philosophy. Upon returning to Vietnam, he helped his brother in his quest for political power, and Nhu proved an astute and ruthless tactician and strategist, helping Diệm to gain more leverage and outwit rivals. During this time, he formed and handpicked the members of the secret Cần Lao Party, which swore its personal allegiance to the Ngô family, provided their power base and eventually became their secret police force. Nhu remained as its head until his own assassination.