What happened to involve the isolationist-toward-Europe U.S. in the affairs of Latin America and the Pacific; ""how it happened"" as extracted from the best studies of each episode and synthesized with vivid dispatch and not unseemly passion. The small but considerable, ""hopelessly inept, even comic"" Mexican War is more acutely depicted in fifty pages than in most full-length books, with liberal quotation from Bernard DeVoto's Year of Decision, 1846, and wise selection from letters, dispatches and eye-witness accounts. The conclusion: ""Even without war the United States would have eventually acquired California and New Mexico, for Mexico was simply too weak, too disorganized to hold on to them."" In the case of ""That 'Splendid Little War' "" with Spain the ""seemingly irresistible urge to stretch outward"" reasserted itself in moral terms, readiness was inflamed by irresponsible journalism, an intercepted message, a large military appropriation, overreaction and unreason re the Maine. . . until the reluctant McKinley succumbed; observed Navy Secretary Long: ""He has been robbed of sleep, overworked, and i fancy that I can see that his mind does not work as clearly and as self-reliantly as it otherwise would."" The outcome? Cuba ostensibly freed, the U.S. incidentally a colonial power. In each of the succeeding sections--""Dollar Diplomacy"" in the Caribbean, ""Intervention in Lebanon,"" ""Again (1965) the Dominican Republic""--the steps to intervention are similarly irrational and obstinate, the results variously futile: in the Dominican Republic, for instance, it was the American-established ""constabulary, led by the American-trained Trujillo, that enabled the 'Benefactor' to take power and rule for three decades with unsurpassed brutality and corruption."" The application here and elsewhere (e.g. Wilson's moral criterion for diplomatic recognition, Dulles' and Johnson's obtuse, ill-informed anti-Communism) to present policy is inescapable; Korea and Vietnam are outside the scope of the book but well within its reach. However it is not a diatribe: the author of America and the Cold War (1969, p. 1274, J-524) builds a strong case on unassailable sources.