In 1949, President Truman shocked America with a terse announcement: “We have evidence that within recent weeks an atomic explosion occurred in the USSR.” The alarm stimulated activity in scientific and political circles, and an arms race was the clear response when on 31 Jan 1950, President Harry S. Truman announced a program to develop the American hydrogen bomb. “I have directed ... work on all forms of atomic weapons, including the so called hydrogen or superbomb. Like all other work in the field of atomic weapons, it is ... consistent with the overall objectives of our program for peace and security ... until a satisfactory plan for international control of atomic energy is achieved.”