Robert McNamara carried the methods of business administration into government and development. After statistical work for the wartime Army Air Forces, he joined Ford Motor Company with the management group known as the Whiz Kids. He rose through financial and executive positions and became Ford's president in 1960, but soon accepted John F. Kennedy's offer to become secretary of defense in January 1961.

At the Pentagon he expanded civilian control through systems analysis, programme budgeting and comparisons of military costs and capabilities. He supported a strategy of flexible response rather than reliance on nuclear retaliation alone and played a major role during the Cuban Missile Crisis. Common planning standards challenged the services' separate preferences, bringing coherence as well as disputes over assumptions and weapons programmes.

Vietnam dominated his later years under Kennedy and Lyndon Johnson. McNamara supported the expansion of American commitments, troop deployments and bombing, using quantitative measures to assess progress. Those measures obscured the war's politics and the limits of American influence. As his doubts increased, he moved toward limiting the bombing and seeking a negotiated outcome, diverging from Johnson. He left the Defense Department in 1968 after becoming one of the principal public architects of a war he increasingly believed could not be won on existing terms.

As World Bank president from 1968 to 1981, he expanded lending and shifted attention toward poverty, rural development, health and education. The Bank's growing research and planning capacity reflected his belief in measurable targets and large institutional programmes, while critics questioned debt, displacement and particular projects. In retirement he promoted nuclear-risk reduction and publicly reconsidered Vietnam, especially in his 1995 memoir In Retrospect. His career exposed the danger of substituting technical measures for political understanding.