In the eight decades since the United States deployed the most destructive weapon ever used, conventional wisdom has held that American leaders were faced with a difficult choice: Invade Japan, which would have cost millions of Japanese and Allied lives in bloody combat or use the fearsome atom bomb in the hopes of convincing the Japanese emperor to surrender. President Truman—in what many have come to regard as an immoral decision—ordered the military to drop the bomb.

Today’s guest is Alex Wellerstein, author of The Most Awful Responsibility: Truman and the Secret Struggle for Control of the Atomic Age. Wellerstein offers a more complex and nuanced portrayal of Truman, showing a president entangled in secrecy, rushing against time, and operating with limited information. Contrary to the long-held belief that Truman was the decisive force behind the bombings, this book reveals how he was largely unacquainted with the specifics of Hiroshima and Nagasaki's targeting until after the fact.

Wellerstein explains how there was no formal decision to use the bomb, nor did President Truman likely know that Hiroshima or Nagasaki were heavily populated cities. Once the bombs were dropped, Truman began a years-long struggle for control of the awesome power of atomic weapons, the ramifications of which are still felt today.