Two superpowers, a hundred new states.

The U.S. and USSR were uneasy allies during WWII; the Yalta Conference (Feb 1945) and Potsdam (July 1945) papered over disagreements about postwar Eastern Europe. By 1947, Stalin had installed communist governments across Eastern Europe; Churchill’s “Iron Curtain” speech (1946) named the divide; Truman’s 1947 doctrine pledged to contain communism. The Marshall Plan (1948) rebuilt Western Europe under U.S. terms; the Soviet Cominform organized the East. The two ideological blocs would dominate global politics for 45 years.

NATO (1949) and the Warsaw Pact (1955) institutionalized the divide. The Cold War “hot” wars happened in proxies: Korea (1950–53), Vietnam (1955–75), Afghanistan (1979–89). The most dangerous moment was the Cuban Missile Crisis (October 1962). Mutually Assured Destruction (MAD) prevented direct nuclear war but raised constant risks. Détente in the 1970s (SALT, Helsinki Accords) eased tensions, then Reagan-era escalation (1980s) preceded the Soviet collapse (1991). The fall of the Berlin Wall (1989) was the symbolic end.

Effects: nuclear arms race (~70,000 warheads at peak); superpower-funded proxy wars and coups in Iran (1953), Guatemala (1954), Congo (1961), Chile (1973); space race (Sputnik 1957, Apollo 11 1969); global ideological competition for influence; CIA and KGB shaping politics in dozens of countries; massive military-industrial sectors in both superpowers. The Cold War also drove decolonization—newly independent states could play superpowers off each other for aid.

Communist revolutions had distinctive paths. Russia (1917): Bolsheviks seized power amid WWI collapse; Stalin built a totalitarian state; Five-Year Plans, Great Purge, victory in WWII. China (1949): Mao’s peasant-based revolution after a long civil war; Great Leap Forward and Cultural Revolution were catastrophic. Cuba (1959): Castro’s 26th of July Movement overthrew Batista; pushed into Soviet orbit by U.S. hostility. Vietnam (1945–): Ho Chi Minh’s Viet Minh fought Japanese, French, then Americans before unifying in 1975.

Decolonization (1947–1975) replaced empires with nation-states. India and Pakistan (1947): Gandhi’s nonviolent campaign + Muslim League pressure + British exhaustion. Vietnam: Viet Minh defeated France at Dien Bien Phu (1954), then beat the U.S. by 1975. Algeria (1954–62): brutal war for independence from France. Sub-Saharan Africa: Ghana first (1957), then most by 1965. Apartheid South Africa held out until 1994. Each independence had its leaders, methods, and aftermaths—but all drew on Enlightenment vocabulary and global anti-colonial solidarity.

Newly independent states faced enormous challenges. Many had borders drawn by colonial powers without ethnic or geographic logic (Africa, the Middle East). Most had economies structured for raw-material export, not industrialization. Many faced superpower interference: U.S.-backed Mobutu in Congo, Soviet-backed Marxist regimes in Ethiopia and Angola. Some pursued non-alignment (Nehru’s India, Tito’s Yugoslavia, Nasser’s Egypt). Others (South Korea, Taiwan, Singapore) industrialized rapidly under authoritarian capitalism. Outcomes ranged widely.

The same era saw mass movements challenging power within established states. The U.S. civil rights movement (1955–68) pushed legal and social desegregation. The anti-apartheid movement built international solidarity that helped end South African white-minority rule (1994). Women’s liberation (second-wave feminism, c. 1963–) reshaped Western law and culture; women’s movements globalized through the UN Decade for Women. Indigenous rights movements (the U.S., Canada, Australia, Latin America) demanded recognition and land. These movements borrowed from each other.

The Soviet collapse came faster than most expected. Mikhail Gorbachev’s glasnost and perestroika reforms (1985–) opened up speech and limited markets but exposed the system’s contradictions. Eastern Europe broke away in 1989: Solidarity-led Poland, the Berlin Wall fell, Czechoslovakia’s Velvet Revolution. The USSR itself dissolved December 1991 into 15 successor states. Effects: Cold War alliances reshaped (NATO expanded east); ethnic conflicts surfaced (Yugoslavia’s wars 1991–2001); a brief U.S.-led “unipolar moment”; eventual Russian revanchism and Chinese rise to fill the vacuum.