At the close of World War II in 1945, the alliance between the United States and the Soviet Union began to unravel. Disagreements over postwar Europe, especially Germany and Eastern Europe, quickly gave way to suspicion and ideological conflict—laying the groundwork for the Cold War. The term “Cold War” itself emerged in mid‑1940s discourse describing this new state of hostilities.:contentReference[oaicite:1]{index=1}
In 1947, President Truman introduced the Truman Doctrine to contain the spread of communism. Soon after, NSC‑68 became a central policy document advocating massive military buildup, military alliances, and ideological resistance to Soviet influence.:contentReference[oaicite:2]{index=2}
The U.S. rolled out the Marshall Plan in 1948 to rebuild Western Europe and limit communist expansion. In response, the Soviet bloc instituted Comecon. Meanwhile, the formation of NATO in 1949 and the Warsaw Pact in 1955 framed a divided Europe in military terms.:contentReference[oaicite:3]{index=3}
Both superpowers exploited espionage and propaganda to exert influence. In the U.S., the Red Scare and high-profile espionage cases—like Klaus Fuchs and the Rosenbergs—fueled fear and policy shifts.:contentReference[oaicite:4]{index=4}
The Cold War never turned “hot” between the superpowers, but it simmered in proxy conflicts. The Korean War (1950–53) remains a defining example, as does the longer Vietnam conflict. These wars represented the ideological battleground between East and West.:contentReference[oaicite:5]{index=5}
The nuclear arms race escalated rapidly after the Soviet Union tested its first atomic bomb in 1949. Launch of Sputnik in 1957 heightened U.S. fears. Missile development culminated in the Cuban Missile Crisis of 1962, the closest the world came to nuclear war.:contentReference[oaicite:6]{index=6}
The Berlin blockade (1948–49) and construction of the Berlin Wall in 1961 symbolized Cold War division. Soviet suppression of uprisings in Hungary (1956) and Czechoslovakia (1968) confirmed Soviet dominance in Eastern Europe.:contentReference[oaicite:7]{index=7}
The 1970s brought a thaw: SALT I and II, the Helsinki Final Act, and diplomatic summits aimed at reducing tensions. Yet behind the scenes, rivalry persisted.:contentReference[oaicite:8]{index=8}
Ronald Reagan’s presidency in the 1980s saw renewed Cold War rhetoric and military buildup—including SDI. Regional conflicts in Latin America, Africa, and Afghanistan further defined a global struggle.:contentReference[oaicite:9]{index=9}
Mikhail Gorbachev’s policies of glasnost and perestroika in the mid‑1980s triggered profound change in the USSR. Revolutions swept Eastern Europe in 1989, followed by reunification of Germany and the dissolution of the Soviet Union in 1991—marking the end of the Cold War.:contentReference[oaicite:10]{index=10}
Cold War economic segregation created severe welfare losses in Eastern bloc countries. Trade barriers—and intra‑bloc commerce—shaped long-term economic outcomes even after the Cold War.:contentReference[oaicite:11]{index=11}
Historians remain divided on origins and responsibility: "orthodox" blame Soviet expansionism, while "revisionists" emphasize American liberal ambitions. The reinterpretation by scholars like Vladislav Zubok argues the Cold War's origins lie more in Western strategic decisions than Soviet aggression.:contentReference[oaicite:12]{index=12}
Although the Cold War formally ended in 1991, its legacies persist: NATO’s continued relevance, nuclear proliferation concerns, great-power rivalry (US, Russia, China), and ideological contestation. Modern geopolitics still echoes the Cold War’s structures.:contentReference[oaicite:13]{index=13}
The Cold War revolutionized global affairs, creating frameworks of alliances, doctrines of deterrence, and proxy conflicts that reshaped nations. It taught the world about the perilous balance of great-power politics, nuclear deterrence, and the transformative power of diplomacy over war.