The antagonism between the Soviet Union and the West that led to Churchill's speech had various origins.

The United Kingdom, France, Japan, Canada, the United States and many other countries had backed the White Russians against the Bolsheviks during the 1918–1920 Russian Civil War, and the fact had not been forgotten by the Soviets.

In the build up to World War II and in the face of the Western appeasement of Adolf Hitler the Soviets organised Anglo-Franco-Soviet negotiations in attempt to form an alliance with the United Kingdom and France to counter Nazi Germany, but were rebuffed due to Western elites' fear of bolshevism and socialist revolution. France and Britain were unwilling to create a formal military alliance with the USSR and apprehensive of a possible war with Hitler while the Western powers remained neutral or tacitly favorable to Hitler.

Subsequently, the Soviet Union signed a non-aggression pact with Nazi Germany, commonly named after the foreign secretaries of the two countries (Molotov-Ribbentrop), on August 23, including a secret agreement to split Poland and Eastern Europe between the two states. One of the intentions of the pact was to create a buffer zone between USSR and Nazi Germany.

Following the war, Stalin was determined to acquire a similar buffer against Germany with pro-Soviet states on its border, leading to strained relations at the Yalta Conference (February 1945) and the subsequent Potsdam Conference (August 1945)

In the West,