yes
I suggest reading Richard Rhodes book: The Making of the Atomic Bomb.
FDR
no, but they were involved as couriers to leak information on the bomb to the USSR.
The United States
Creation of the atomic bomb
well, the atomic bomb research was done by Robert oppenheimer. the original creation or idea was from albert Einstein
One was the discovery of Plutonium.
H.G Wells
Yes
Albert Einstein did not invent the atom bomb. He was not directly involved in its creation, but his research on mass-energy equivalence (E=mc^2) laid the theoretical groundwork for nuclear fission, which eventually led to the development of the atomic bomb by scientists during World War II.
Albert Einstein and Robert Oppenheimer did not invent the atomic bomb; rather they were involved in the scientific and theoretical developments that led to its creation. The atomic bomb was developed as part of the Manhattan Project during World War II in response to fears that Nazi Germany was working on similar weapons. It was ultimately used by the United States in the bombings of Hiroshima and Nagasaki in 1945.
The creation of the Atomic Bomb. Southwest art.