Franklin Delano Roosevelt

Albert Einstein, Alexander Sachs and Leo Szilard all wrote letters to the President to pursuade him to fund a program to develop a nuclear bomb.

On December 6th, 1941 he commits $2 billion dollars to the Manhattan Engineering District to build the atom bomb. This would equate to over 50 billion dollars today.

Most significant was the decision to actually drop the bomb on civilians. This decision fell upon Harry S. Truman as Roosevelt died 4 months before HIroshima.