Although post-war Europe dominated Potsdam`s agenda, war in the Pacific was off the scene. Truman received news of the success of the atomic bomb test shortly after his arrival in Potsdam; He told Churchill the news, but only occasionally mentioned “a new weapon” to Stalin. Truman continued to ask for Stalin`s help against Japan, but he knew that if the bomb succeeded, Russian help would not be needed. In fact, the bomb would give the United States unprecedented power in the post-war world. The Reader`s Companion to American History. Eric Foner and John A. Garraty, Editor-in-Chief. Copyright © 1991 by Houghton Mifflin Harcourt Publishing Company. All rights reserved. Truman was much more suspicious of the Soviets than Roosevelt and became increasingly suspicious of Stalin`s intentions.  Truman and his advisers regarded Soviet action in Eastern Europe as aggressive expansionism incompatible with the agreements to which Stalin had committed himself in February in Cantta.
In addition, Truman was alerted to possible complications elsewhere when Stalin rejected Churchill`s proposal to withdraw the Allies from Iran before the timetable agreed at the Tehran conference. The Potsdam conference was the only time Truman met Stalin in person.   At the Von Yalta conference, France was granted an occupation zone in Germany. . . .