There have been many conflicts of opinion when understanding and interpretting the events of the Cold War and its origin. Generally, it is understood there are three main categories an historian may fall in to: a 'Realist', 'Liberal', or 'Critical' approach. To compare Realist and Liberal understandings of the Cold War with those of Critical understandings it is neccesary to establish the key mindsets of the approaches. The Realist and Liberal understandings are largely similar however disagree on a number of viewpoints. Realist approaches agree that the two post-war superpowers; the USA and the USSR, were the most central figures playing the role of the often described 'ultimate Balance of Power' during the period 1945-1990. They agree the alliance system was mainly that of a Western: US, West Europe and Japan against an Eastern: USSR and East Europe. Realists take the view that world politics is lead by States persuing power and national security. They take a Darwinistic idea that states are always competing for this power and are always unsure of other states plans. Ultimately this meant they understood the US as wanting to overcome the Soviet threat as well as promoting capitalism thus protecting their interests in other areas around the world and the USSR of wanting to expand its territory, influence and communist ideology. Both of these presumed targets share qualities of before seen imperialism. The US looking to expand its trade and the USSR its territory. Realists saw communism as a threat to western values and capitalism as an instrument of freedom. They believe the US and West were merely containing the Soviet threat.
A Liberal approach tends to focus less on the conflict and competition struggle of states but favours the idea that institutions helped to accomplish the persuit of national security. They also put more influence on the role of world politics as opposed to the conflict of the super powers and believed democracy was the most effective...