The onset of the Cold War after World War II was driven by ideological and geopolitical factors. Ideologically, the stark contrast between the capitalist democracy of the United States and the communist dictatorship of the Soviet Union created a fundamental rift. The U.S. promoted free markets, political freedoms, and individual rights, while the USSR advocated for state control of the economy and a one-party system suppressing political dissent.

Geopolitically, the power vacuum in Europe and Asia post-World War II intensified tensions. The U.S. aimed to contain the spread of communism through strategies like the Truman Doctrine and the Marshall Plan, which provided economic aid to rebuild war-torn Europe and prevent communist influence. The Soviet Union, on the other hand, sought to expand its sphere of influence by establishing communist governments in Eastern Europe, creating a buffer zone against potential Western aggression.

The division of Germany, the Berlin Blockade (1948-1949), and the subsequent Berlin Airlift exemplified the physical and ideological divide. The formation of NATO in 1949 and the Warsaw Pact in 1955 solidified the military alignments. The mutual distrust and competing visions for world order between the U.S. and the USSR led to a prolonged period of political and military tension known as the Cold War.