Lewy contends that the Vietnam War was legal and not immoral. In recalling the 1971 congressional testimony of some US veterans who were critical of the war, one of whom compared US action in Vietnam to genocide, Lewy suggests that some "witnesses sounded as if they had memorized North Vietnamese propaganda." The book is broadly critical of domestic opponents of American participation in the Vietnam War. In using the phrases "peace activists" or "peace demonstrations", Lewy often puts quotation marks around the word "peace", implying alternative motivations for the activism. The author suggests there may be a connection between cases of sabotage in the Navy and the anti-war movement:  Between 1965 and 1970, the Navy experienced a growing number of cases of sabotage and arson on its ships, but no evidence could be found that antiwar activists had directly participated in a sabotage attempt on a Navy vessel. Cases of fragging and avoidance of combat may well have been instigated at times by antiwar militants, though no hard evidence of organized subversion was ever discovered. Lewy criticized Noam Chomsky in the book for his role in proliferating charges of American war crimes through the aegis of the Committee of Concerned Asia Scholars, which Lewy characterizes as part of a "veritable industry" of war crimes allegations. Chomsky replied to the criticism with an article entitled "On the Aggression of South Vietnamese Peasants against the United States", in which he suggests that "Lewy is not writing just military history but a moral tract." He said,  In discussing the treatment of prisoners, Lewy shows his reasonableness by acknowledging "several cases of US maltreatment and torture." These are treated with antiseptic brevity, and Lewy takes pains to put them into a context of the "frustration resulting from fighting an often unseen enemy, the resentments created by casualties," etc. In dealing with Communist inhumaneness, however, he gives a plenitude of detail, with an unconcealed moral indignation totally absent from his grudging admission of US-Saigon torture, and factors that might explain such acts by the enemy are treated with sarcasm. He even matter-of-factly explains Saigon torture: "The police were not highly professional, prison guards were underpaid, and South Vietnamese have a low regard for human life." "America in Vietnam" has frequently been assailed as a "revisionist" text. The book has been referred to as "a classic revisionist interpretation of the war", "the first and most impressive of the revisionist accounts" of the Vietnam war, and "one of the earliest and most sophisticated of revisionist works".