The deaths from incineration and radiation of some 200,000 residents of Hiroshima and Nagasaki in August 1945 dramatically ushered in the atomic age, surely one of the most significant developments in recorded history. Among its more profound consequences, the destruction of these two cities contributed to the origins of the Cold War. The American possession of a monopoly on atomic power and the subsequent effort of Secretary of State James F. Byrnes to practice atomic diplomacy rapidly catalyzed Soviet American disagreements into an implacable confrontation.

Assessments of the motives behind the decision to drop the bombs have tended to cluster diplomatic historians into opposing camps. Those labeled "traditionalist" or "orthodox" echo Secretary of War Henry L. Stimson's contention that the use of the bomb was militarily necessary to force Japan's surrender as quickly as possible and with the least possible loss of American lives. Contrarily, "revisionists" generally argue that the bombs were not vital to defeating Japan but were utilized to influence Soviet behavior.

In the following two selections, Robert Messer and Gar Alperovitz reevaluate this clash of historical interpretations. They offer new evidence on President Truman's personal views, speculate about the implications, and caution the reader about making conclusive historical judgments on the basis of fragmentary evidence.