After World War II, Europe faced a new political and cultural order. This order was defined by a number of developments, including the cold war. The war destroyed the traditional preeminence of western Europe, leaving the U. S. and U. S. S. R. to confront each other as ideologically opposed superpowers. As Russia imposed pro-Soviet regimes on eastern Europe, the U. S. adopted the Truman Doctrine of containment and launched the Marshall Plan to build anti-communist allies in western Europe. The U. S. also expanded its national security establishment and founded NATO as a military bulwark against Soviet aims. Fearing U. S. nuclear power, the Soviets developed their own atomic-weapons. The resulting arms race nearly exploded during the Cuban Missile Crisis. To curb this race, some U. N. members signed the Nuclear Non-Proliferation Treaty, and the super powers undertook SALT. The launch of sputnik prompted a space race during which the U. S. landed a man on the moon. The super powers often clashed through regional conflicts, including the Korean and Vietnam wars. Despite its defeat in the latter, the U. S. continued to represent a political, social, and economic ideal for much of the world.

As the cold war commenced, Europe began rebuilding. Using the U. S. as a model for cooperation, European nations joined unions such as the ECSC, EEC, and EC. Britain gradually rebuilt its shattered economy, first through government controls, and later through free enterprise encouraged by Thatcher. Immigration and IRA terrorism created civic tensions, and EC membership did little to break English insularity. Post-war France faced the problem of decolonization. The Algerian war created a political crisis defused by de Gaulle, who ruled as a strong executive until he resigned as a result of the 1968 student/worker uprising. A weak centrist coalition gave way to Mitterand's moderate socialist government that maintained France's position as a leader of European unity. Despite political fractiousness and regional divisions, Italy managed to build a strong economy. Germany emerged from the war divided. Under the leadership of chancellors including Adenauer, Brandt, and Kohl, West Germany achieved economic strength and became a leading nation in the movement for European unity.

Russia emerged from the war devastated but politically unchanged. Stalin maintained his totalitarian grip and extended it over eastern Europe, forming the Soviet Bloc. Khrushchev encouraged a thaw and acknowledged Stalin's crimes, but his aggressive pursuit of Soviet superiority caused his politburo to replace him with an oligarchical regime led by Brezhnev. During these years Poland, Hungary, and Czechoslovakia tried to resist Soviet dominion, but only Poland managed to avoid Warsaw Pact intervention. Dissidents denounced the Soviet system, but no significant change occurred until Gorbachev introduced his glasnost and perestroika. These policies, as well as the economic strain of the arms race with the U. S., hastened the fall of the U. S. S. R.

After the war, decolonization dissolved overseas empires. Asia decolonized first as the Philippines, Pakistan, India, Ceylon, Burma, and Indonesia became independent nations. Communist China encouraged anticolonial movements in southeast Asia, helping to set the stage for the Vietnam war. Between 1950 and 1975, European nations decolonized Africa. Throughout the world decolonization often left regimes unprepared for the tasks of government, and cold war politics encouraged bloody civil wars among factions bent on ruling the new nations.