This book has sought to provide a fresh account of President Lyndon B. Johnson's conduct of foreign affairs, filling a gap in the literature. It is noted that the President established a White House foreign policy operation responsive to his own needs and inclinations. Although his disinterest towards intelligence reports is not to his credit (he felt that such assessments merely complicated the making of policy), he sought counsel from a wide range of sources for the benefit of hearing different views as well as to legitimise existing policies. Concerns about the United States' international credibility were foremost among the reasons for the escalation of the US commitment in Vietnam in 1965. Historians should seek to judge the decision to ‘Americanise’ the war on its own terms, in and of itself, rather than in the light of how the war turned out – defeat was not foreordained. In some ways the American military performed adequately in Vietnam, crushing the Tet Offensive of 1968, for example. However, the guerrilla element of the war was not given sufficient attention and by 1968 the death toll had exceeded what in the United States was generally considered to be an acceptable sacrifice.

Britain, the United States' most important ally, provided diplomatic support for the United States' stance in Vietnam but would not provide troops, and the ‘dissociation’ episode in 1966 showed that even the diplomatic support had its limits. Differences over Vietnam along with the British inability to maintain international defence commitments weakened the high-level Anglo-American relationship, although Britain remained a major ally by virtue of its continued commitment to the NATO theatre.