Robert McNamara was the United States Secretary of Defence under both John F. Kennedy and Lyndon Johnson. His leadership and decisions were a critical factor in US troop build-up in Vietnam in the 1960s. The following extract is from McNamara’s 1995 memoir, titled In Retrospect:

“I believe we could and should have withdrawn from South Vietnam either in late 1963 amid the turmoil following Diem’s assassination or in late 1964 or early 1965 in the face of increasing political and military weakness in South Vietnam. We misjudged the geopolitical intentions of our adversaries (in this case, North Vietnam and the Viet Cong, supported by China and the Soviet Union), and we exaggerated the dangers to the United States of their actions. We viewed the people and leaders of South Vietnam in terms of our own experience. We saw in them a thirst for—and a determination to fight for—freedom and democracy. We totally misjudged the political forces within the country. We underestimated the power of nationalism to motivate a people (in this case, the North Vietnamese and Viet Cong) to fight and die for their beliefs and values. Our misjudgments of friend and foe alike reflected our profound ignorance of Vietnam’s history, culture, and politics, plus the personalities and habits of its leaders.”