Cold War Background

There is disagreement among historians regarding the starting point of the Cold War. While most historians trace its origins to the period immediately following World War II, others argue that it began towards the end of World War I, although tensions between the Russian Empire, other European countries and the United States date back to the middle of the 19th century.
As a result of the 1917 Bolshevik Revolution in Russia (followed by its withdrawal from World War I), Soviet Russia found itself isolated in international diplomacy. Leader Vladimir Lenin stated that the Soviet Union was surrounded by a "hostile capitalist encirclement", and he viewed diplomacy as a weapon to keep Soviet enemies divided, beginning with the establishment of the Soviet Comintern, which called for revolutionary upheavals abroad.Subsequent leader Joseph Stalin, who viewed the Soviet Union as a "socialist island", stated that the Soviet Union must see that "the present capitalist encirclement is replaced by a socialist encirclement." As early as 1925, Stalin stated that he viewed international politics as a bipolar world in which the Soviet Union would attract countries gravitating to socialism and capitalist countries would attract states gravitating toward capitalism, while the world was in a period of "temporary stabilization of capitalism" preceding its eventual collapse.
Various events before the Second World War demonstrated the mutual distrust and suspicion between the Western powers and the Soviet Union, apart from the general philosophical challenge the Bolsheviks made towards capitalism.There was Western support of the anti-Bolshevik White movement in the Russian Civil War, the 1926 Soviet funding of a British general workers strike causing Britain to break relations with the Soviet Union, Stalin's 1927 declaration of peaceful coexistence with capitalist countries "receding into the past,"conspiratorial allegations during the 1928 Shakhty show trial of a planned British- and French-led coup d'état, the American refusal to recognize the Soviet Union until 1933 and the Stalinist Moscow Trials of the Great Purge, with allegations of British, French, Japanese and Nazi German espionage. However, both the US and USSR were generally isolationist between the two world wars.
The Soviet Union initially signed a non-aggression pact with Germany. But after the German Army invaded the Soviet Union in June 1941 and the Japanese bombed Pearl Harbor in December 1941, the Soviet Union and the Allied powers formed an alliance of convenience. Britain signed a formal alliance and the United States made an informal agreement. In wartime, the United States supplied both Britain and the Soviets through its Lend-Lease Program. However, Stalin remained highly suspicious and believed that the British and the Americans had conspired to ensure the Soviets bore the brunt of the fighting against Nazi Germany. According to this view, the Western Allies had deliberately delayed opening a second anti-German front in order to step in at the last moment and shape the peace settlement. Thus, Soviet perceptions of the West left a strong undercurrent of tension and hostility between the Allied powers.