Just as famines and plagues can provide opportunities for medical research, the unhappy course of United States relations with Vietnam is a prime source of evidence for students of American political institutions. How Presidents Test Reality draws on the record of American decision making about Vietnam to explore the capacity of top government executives and their advisers to engage in effective reality testing. Authors Burke and Greenstein compare the Vietnam decisions of two presidents whose leadership styles and advisory systems diverged as sharply as any in the modern presidency. Faced with a common challenge--an incipient Communist take-over of Vietnam--presidents Eisenhower and Johnson engaged in intense debates with their aides and associates, some of whom favored intervention and some of whom opposed it. In the Dien Bien Phu Crisis of 1954, Eisenhower decided not to enter the conflict; in 1965, when it became evident that the regime in South Vietnam could not hold out much longer, Johnson intervened. How Presidents Test Reality uses declassified records and interviews with participants to assess the adequacy of each president's use of advice and information. This important book advances our historical understanding of the American involvement in Vietnam and illuminates the preconditions of effective presidential leadership in the modern world. "An exceptionally thoughtful exercise in what 'contemporary history' ought to be. Illuminates the past in a way that suggests how we might deal with the present and the future." --John Lewis Gaddis "Burke and Greenstein have written what amounts to an owner's manual  for operating the National Security Council....This is a book Reagan's  people could have used and George Bush ought to read." --Bob Schieffer, The Washington Monthly