Zinn argues in Chapter 16 that the United States, while clearly engaged in a war with an "evil" enemy, was not primarily driven by altruistic motives to fight. Rather, the US entered the war to uphold its interests in the Pacific, which were threatened by Japanese aggression. Zinn draws parallels between American repression of minorities, particularly African-Americans in the Jim Crow South, and the internment of Japanese-Americans in the West to argue that the claim that the United States was engaged in a struggle for human rights is at its heart hollow. He also emphasizes internal dissent against the war, particularly by labor unions and African-Americans, to cast doubt on the assumption that Americans were thoroughly behind the war. Finally, he argues that the bombing campaigns against Germany and Japan, and particularly the dropping of atomic bombs on Hiroshima and Nagasaki, were unjustified acts of mass murder.
Like most of Zinn's book, this chapter has come under intense scrutiny, both by conservative commentators who view it as an outright fabrication and, more tellingly, by professional historians who regard the work as a gross oversimplification of the forces that drove the US to war. Leftist historian Michael Kazin, hardly an ideological opponent of Zinn, wrote a famous and scathing review in Dissent, describiing the 2004 edition of the book as suffering from ideological myopia, hopeless naivete, and, ultimately, very shoddy scholarship. His analysis of Zinn's chapter on World War II illustrates the point:
Of course, [Zinn argues] as an imperial bully, the United States had no right, in World War II, "to step forward as a defender of helpless countries." Zinn thins the meaning of the biggest war in history down to its meanest components: profits for military industries, racism toward the Japanese, and the senseless destruction of enemy cities-from Dresden to Hiroshima. His chapter on that conflict does ring with a special passion; Zinn served as a bombardier in the European theater and the experience made him a lifelong pacifist. But the idea that Franklin Roosevelt and his aides were motivated both by realpolitik and by an abhorrence of fascism seems not to occur to him.
Kazin's review suggests a view common to academic historians. Zinn distills the complex events of World War II down to a handful of causes that fit neatly in his construct of history as a struggle between the common people and the elites that oppress him. In particular, he fails to acknowledge that the vast majority of Americans supported the war effort, instead choosing to select sources that overemphasize the degree of opposition to the war.