On This Day, April 25, 1945, just 12 days after being sworn in as the 33rd President of the United States following the death of Franklin D. Roosevelt, Harry S. Truman received a top-secret briefing that unveiled the full, jaw-dropping details of the Manhattan Project.
Secretary of War Henry L. Stimson informed the new president about the pioneering scientific undertaking to develop the world’s first atomic bombs. Truman learned of the colossal efforts underway at remote facilities across the country to enrich uranium and produce plutonium for these powerful new weapons.
The very existence of the Manhattan Project had been kept under extreme secrecy, even from Vice President Truman until he unexpectedly assumed the presidency on April 12th. The scale, costs, and revolutionary implications of harnessing nuclear fission were nothing short of staggering.
Truman, a former artillery officer in World War I, immediately grasped the potential for these new “atomic bombs” to bring an end to the raging world war by forcing the unconditional surrender of Imperial Japan. But he also understood their earth-shattering destructive capabilities that could alter global politics forever.
Within four months after this briefing, on August 6th and 9th, 1945, two atomic bombs were detonated over the Japanese cities of Hiroshima and Nagasaki at Truman’s command. This ushered in the infamous Nuclear Age with all its lingering complexities.
The April 25th Manhattan Project disclosure to Truman marked a definitive turning point not just in World War II, but for all of human history going forward.
