“So a lot of our opinions about what really drove the United States to drop the bomb is guesswork.” “The bomb was so top secret that there were no formal meetings about it, there was no official discussion about what to do, there wasn't the kind of decision-making process that we have with most kinds of policy,” says Campbell Craig, professor of international relations in the School of Law and Politics at Cardiff University and co-author of The Atomic Bomb and the Origins of the Cold War (with Sergey Radchenko). READ MORE: WWII Ends: 22 Photos of Giddy Celebrations After Allied VictoryĮven today, historians continue to disagree over whether or not the Truman administration made the decision to drop the atomic bomb for political reasons-namely, to intimidate the Soviet Union-rather than strictly military ones. What Happened at the 1941 Babi Yar Massacre? Igor Kurchatov was the nuclear physicist who headed up the Soviet atomic bomb project-the Soviet equivalent, in other words, of Manhattan Project mastermind J. diplomatic history at the University of California and the author of The Winning Weapon: The Atomic Bomb in the Cold War and Brotherhood of the Bomb. “We now know that Stalin immediately went to his subordinates and said, we need to get Kurchatov working faster on this,” says Gregg Herken, emeritus professor of U.S. While Stalin didn’t take the atomic threat as seriously during wartime as some of his spies did-he had other problems on his hands, thanks to the German onslaught and occupation-Truman’s words at Potsdam made more of an impact than the president realized. READ MORE: Harry Truman and Hiroshima: Inside His Tense A-Bomb Vigil Roosevelt’s death, Soviet intelligence had begun receiving reports about the project as early as September 1941. program to develop atomic weapons just three months earlier, after Franklin D. In fact, while Truman himself had first learned of the top-secret U.S. side was that the Soviet premier didn’t know the exact nature of the new weapon. Truman never mentioned the words “atomic” or “nuclear” to Stalin, and the assumption on the U.S.