How do you plan for the most destructive war the world has never seen before? After the bombs were dropped on Hiroshima and Nagasaki, American leaders had to figure out how – or whether – nuclear weapons would be used in the wars of the future. In the pilot episode of A Most Terrible Weapon, Usha looks at the very first nuclear war plans, the debates inside the Truman administration about whether the bomb could ever be used again, and a terrifying new development – the arrival of the hydrogen bomb.

Featuring: Dr. Lynn Eden, Dr. Marc Trachtenberg, Dr. Alex Wellerstein