Cold War episode 1 – Comrades 1917-1945: Though ideological enemies, the Soviet Union and the U.S. are allies against Hitler during WWII. At the end of the war, Europe is divided, and the one-time allies now confront each other. The U.S. has the atomic bomb. The Russian Revolution of 1917, followed by the Russian Civil War caused a rift between the Soviet Union and the United States. But when President Franklin Roosevelt took office in 1933, diplomatic and trade relations between the two countries resumed. The relationship was strained yet again after the USSR annexed the Baltic States and signed a non-aggression pact with Nazi Germany.