To What Extent Was the Soviet Union's Expansion Into Eastern Europe the Main Cause of the Intensification of the Cold War 1945-1956?

There are many different historians’ views on what caused the Cold War, the three main schools of thought are Orthodox, Revisionist and Post revisionist. They all blame it Cold War on the USSR or the US. However there is not just one group you can blame which is examined in the Post Revisionist view.

To start with the Soviet Union and their expansion into Eastern Europe was a main cause for the Cold War and are examined by Orthodox historians who believe that the cause was the USSR. They believe that the spread of communism between 1945 and 1949, which is happening by expansion into Eastern Europe, showed a threat to the Western Powers and therefore they believed they needed to go against them to prevent this from further happening. Also they went against agreements made at Yalta in February 1945, as Stalin felt that the security of the

Soviet Union wasn’t the concern of the US and therefore separated the Grand Alliance, along with the Poland question and the failure to conduct free elections in Poland due to the worry of the security of Russia if Poland became democratic. Next there are the problems that were caused by the Berlin Blockage in June 1948 when all ground entrances into western Berlin, which were in the middle of soviet zones, became blocked off. This caused western powers like Britain and USA to become very suspicious of the Soviet Union and its long term aim of spreading communism by blocking western powers in Berlin. This school of thought was mainly the school of thought for America in the 1950’s and 1960’s.
However other historians like the Revisionist view believe that the cause of the Cold War lies with the USA, they believe this due to the use of nuclear weapons, atomic bomb, which lead to the USSR seeing it as a threat to the future security of the Soviet Union and needed to create security by creating a buffer from western Europe with allied countries and trying to avoid encirclement form Capitalists countries like the US and Britain...