President Truman's Decision to Drop Atomic Bombs on Japan

In the summer of 1945, President Truman had a tough decision to make: how to end the Pacific war on terms most advantageous to the U.S. To mark the 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945, the National Security Archive is updating and analyzing the events leading up to that fateful decision. President Harry Truman's diary is one source historians have evaluated for information about his decisions at the end of World War II.

Truman and his advisers made the only decision they could have made; indeed, considered in the context of World War II, it wasn't really a decision at all. The U.S. atomic bomb attack on the people of Hiroshima at 8:15 a.m. on August 6, 1945, and the second bombing of Nagasaki on August 9, led to Japan's surrender and the end of World War II. Scholars, like contemporary observers, continue to argue heatedly over the quality of President Truman's strategy and diplomacy.

Harry Truman used antisemitic slurs in private. But his surprise decision 75 years ago to recognize Israel, launching a fierce alliance, shows the complexity of his leadership. Presidents Truman, Eisenhower, Kennedy, Johnson, and Nixon all deepened U.S. involvement in the decades-long conflict.

In his first days as president in April 1945, Truman walked into his predecessor's White House Map Room. The decision to use atomic bombs to end the war was a controversial one, but Truman believed it would save lives in the long run. The bombings remain a topic of debate and historical scrutiny.

The White House and Congress were both involved in the decision-making process regarding the use of atomic bombs. Truman's choice had long-lasting effects on international relations and national security. The U.S. was able to assert its dominance and bring an end to the conflict, but at a great human cost.