19.1 A New Global Conflict

Amid the rubble of war, a new power structure emerged. In Europe, Germany was defeated. France and Britain were exhausted. Two other powers, the United States and the Soviet Union, emerged as superpowers, nations with the economic resources and military might to dominate the globe. The United States abandoned its traditional policy of isolationism to counter what President Truman saw as the communist threat.

Photo of three men shaking hands, front left to right Churchill, Truman, and Stalin, in front of a group of men.

Churchill, Truman, and Stalin shake hands at the Potsdam Conference, held in Germany in July, 1945. Still at war with Japan, the leaders of the wartime alliance hid the growing tensions among them.


  • Summarize how the outcome of World War II contributed to the development of the Cold War.
  • Identify continuing Cold War conflicts in Germany and Eastern Europe.
  • Explain the growth of the nuclear arms race.
  • Analyze how the Cold War became a global conflict.
  • Compare the United States and the Soviet Union in the Cold War.

Key Terms

  • superpower
  • Cold War
  • Truman Doctrine
  • containment
  • Marshall Plan
  • North Atlantic Treaty Organization (NATO)
  • Warsaw Pact
  • détente
  • Fidel Castro
  • John F. Kennedy
  • ideology
  • Nikita Khrushchev
  • Leonid Brezhnev

Wartime Alliance Breaks Apart

Tensions Grow Among the Allies

During the war, the Soviet Union and the nations of the West had cooperated to defeat Nazi Germany. By 1945, however, the wartime alliance was crumbling. Conflicting ideologies and mutual distrust soon led to the conflict known as the Cold War.

The Cold War was a state of tension and hostility between nations aligned with the United States on one side, and the Soviet Union on the other side. There was no armed conflict between the United States and the Soviet Union, the major rivals during the Cold War.

At wartime conferences and postwar discussions, the Allies had forged a united front. At the Yalta Conference, Churchill and Roosevelt accepted some of Stalin's demands regarding Eastern Europe. They also agreed to the Allied occupation of Germany and the principle of reparations. Despite these agreements, tensions among the Allies deepened once the war ended, helping to create a divided world during the Cold War.

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Table of Contents

World History Topic 1 Origins of Civilization (Prehistory–300 B.C.) Topic 2 The Ancient Middle East and Egypt (3200 B.C.–500 B.C.) Topic 3 Ancient India and China (2600 B.C.–A.D. 550) Topic 4 The Americas (Prehistory–A.D. 1570) Topic 5 Ancient Greece (1750 B.C.–133 B.C.) Topic 6 Ancient Rome and the Origins of Christianity (509 B.C.-A.D. 476) Topic 7 Medieval Christian Europe (330–1450) Topic 8 The Muslim World and Africa (730 B.C.-A.D. 1500) Topic 9 Civilizations of Asia (500–1650) Topic 10 The Renaissance and Reformation (1300–1650) Topic 11 New Global Connections (1415–1796) Topic 12 Absolutism and Revolution Topic 13 The Industrial Revolution Topic 14 Nationalism and the Spread of Democracy (1790–1914) Topic 15 The Age of Imperialism (1800–1914) Topic 16 World War I and the Russian Revolution (1914–1924) Topic 17 The World Between the Wars (1910–1939) Topic 18 World War II (1930–1945) Topic 19 The Cold War Era (1945–1991) Topic 20 New Nations Emerge (1945–Present) Topic 21 The World Today (1980-Present) United States Constitution Primary Sources 21st Century Skills Atlas Glossary Index Acknowledgments