The primary source of conflict during the Cold War was the ideological struggle between the United States and the Soviet Union. This rivalry was characterized by competing political systems: capitalism versus communism. The conflict manifested in various forms, including nuclear arms races, proxy wars, and intense diplomatic tensions. Key events, such as the Cuban Missile Crisis and the Vietnam War, exemplified these hostilities. The Cold War deeply influenced global alliances, leading to the formation of military and economic blocs, significantly shaping international relations throughout the second half of the 20th century.