Why had the Superpowers become suspicious of each other by March 1946, when Churchill made his important speech at Fulton?

The USA and the USSR became suspicious of each other because they had different beliefs.  The Soviet Union was a Communist country, ruled by a dictator, who cared little about human rights.  The USA was a capitalist democracy which valued freedom.  The superpowers’ different lifestyles caused suspicion of each others’ motives and actions.  This caused friction because the two sides did not understand each other.  They believed that their way of life was better, and tended to despise the way of life of the other side.  They wanted to prove that their way of life was superior – this again caused them to do things which caused confrontation.  In these ways, different beliefs helped to create the Cold War. 

Both the USA and the USSR had very different aims.  Stalin wanted huge reparations from Germany, and a ‘buffer’ of friendly states to protect the USSR from being invaded again.  He systematically stripped the Soviet zone in eastern Germany of wealth and agricultural and industrial machinery.  Britain and the USA opposed this because they believed that it was simply Stalin tightening his grip on eastern Germany.  Britain and the USA wanted to protect democracy, and help Germany to recover.  They were worried that large areas of eastern Europe were falling under Soviet control.  The western powers action caused hostility in Russia because Stalin feared that they were setting up a strong Germany which might again threaten the USSR. 

Resentment about history made the USA and the USSR suspicious of each other.  The Soviet Union could not forget that in 1918 Britain and the USA had tried to destroy the Russian Revolution.  Stalin also thought that they had not given him enough help in the Second World War.  At the same time, Britain and the USA could not forget that Stalin had signed the Nazi-Soviet Pact with Germany in 1939.  These long-standing hatreds from history made both sides suspect each others’ motives and actions.  There may have even been an element of revenge for the past.  In these ways, the past helped to create the Cold War. 

Finally, because neither side trusted each other, events made them hate each other more. 

The Yalta Conference (Feb 1945) caused problems because, although on the surface, the conference seemed successful, behind the scenes, tension was growing.  After the conference, Churchill wrote to Roosevelt that ‘The Soviet union has become a danger to the free world.’ At the Potsdam Conference (Jul 1945) the arguments came out into the open – Russia and America openly disagreed about the details of how to divide Germany, the size of reparations Germany ought to pay, and Soviet policy in Poland. 

Also, Russia’s salami tactics (taking over the countries of eastern Europe, slice by slice 1945–48) caused suspicion because – although Russia claimed it was simply building a buffer zone between Germany and Russia – the western powers believed that the Soviets were building an empire in eastern Europe.  At Fulton, Churchill said that eastern Europe was cut off from the free world by ‘an iron curtain’.  Behind that line, he said, the people of eastern Europe were ‘subject to Soviet influence .  .  .  totalitarian control [and] police governments’. 

So, although the Russians claimed that Churchill’s Fulton speech caused the Cold War, the beliefs, aims, history of the two sides, and events leading up to 1946, had created the conditions which created hostility.