What about Communist infiltration of the Manhattan Project
How could you ignore the communist infiltration of the Manhattan Project, and the turning over of classified materials to the USSR (which had been Hitler's staunch ally from August 1939 through June 1941. Communist Party USA members, who had been anti-Nazi until the Nazi-Soviet Non-Aggression Pact of August 1939, attacked F.D.R., attacked liberals who remained anti-Nazi (now that Nazi Germany was the USSR's ally, to be anti-Nazi was to be anti-Soviet/anti-communist, and did everything in their power to stop aid to Great Britain in its death struggle with Hitler's Germany (a regime being supplied by the USSR up until the very day Hitler invaded the country).
Communist Party members answered to Moscow's tune. I'm no anti-Red (I'm actually a Democrat and would be a member of the socialist wing of a labor party if we had one; a social Democrat), but them's the facts baby, facts conveniently forgotten by many (except the boring, braying dogs of the right). Progressives, liberal Democrats and non-Stalinist socialists despised "Communists" (CPUSA members) for good reason.
Incidentally, if the Japanese had attacked Siberia (they had been soundly repulsed by the Red Army in two previous border battles in the late 1930s) in 1941 Hitler's Operation Barbarossa might have succeeded. The thing is, at the time this movie starts, it had only been a year since the USSR and the Communist Party USA had been allies of Hitler.
Of course, Oppenheimer's relationship with a Communist (his wife was also a commbnist, wasn't she) would have been a serious mater, as Stalin and the USSR had been allied with Hitler, invaded Poland two weeks after Hitler did, then annexed the Baltic states and attacked Finland.
THE USSR MADE HITLER'S ATTACK ON BOTH POLAND AND WESTERN EUROPE AND THE BALKANS POSSIBLE. THE NAZI-SOVIET NON-AGGRESSION PACT TRIGGERED WORLD WAR II.
This pap was about as weak as dishwater.