In many respects, as he confessed later in life, McNamara’s mistakes were mistakes of omission not commission. They were mistakes nonetheless. His mistakes raise important counterfactual questions. What if McNamara had inherited another model for civil-military relations? What if the State Department had been stronger? Could a counterinsurgency strategy have worked in South Vietnam? Could different funding arrangements in Washington have produced different outcomes? What if Johnson had been less of a New Dealer? What if McNamara had defined “loyalty” differently? What would President Kennedy have done?

The book provides a reassessment of Robert S. McNamara’s decisions during the Vietnam War. It situates him at the end of a historical process for the Office of the Secretary of Defense (OSD), a young agency that was still in flux and trying to define the proper balance between civilian and military advisors. McNamara’s concern for economic issues meant he resisted international commitments, in Vietnam and elsewhere. His idiosyncratic views on loyalty led him to self-censor and adopt public positions that were at odds with his private views. He ultimately became the spokesperson for a war that he had resisted. The book has benefited from a host of new sources, including McNamara’s papers at the Library of Congress, recently declassified Defense Department materials and the private diaries of his assistant for International Security Affairs, John T. McNaughton.