What was the Cold War and what events caused it? Cold War is the term used to describe the intense rivalry that developed after World War II between groups of Communist and non-Communist nations. On one side were the Union of Soviet Socialist Republics (U.S.S.R.) and its communist allies that referred to as the Eastern bloc. On the other side were the United Staes and its democratic allies, usually referred to as the Western bloc. Cold War was characterized by mutual distrust, suspicion, and misunderstandings by both the United States and the Soviet Union, and their allies. The United States accused the Soviet Union of seeking to expand Communism throughout the