Détente and the end of the Cold War, 1970-1991
What was Détente?
By the early 1970s, both the USA and Soviet Union had accumulated enough nuclear weapons to destroy each other many times over. The Vietnam War had damaged American confidence and drained resources. Both superpowers had incentives to reduce tensions and limit the escalating cost of the arms race. The result was détente — a French word meaning “relaxation.” It marked a pragmatic recognition by both sides that confrontation carried unacceptable risks.
SALT I (1972) was the first major nuclear arms limitation agreement, signed by President Nixon and Soviet leader Brezhnev. It froze the number of intercontinental ballistic missiles (ICBMs) and submarine-launched missiles each side could hold. SALT II (1979) set further limits on nuclear warheads but was never ratified by the US Senate after the Soviet invasion of Afghanistan in December 1979.
Nixon Opens Relations with China, 1972
One of the most unexpected diplomatic moves of the Cold War was Nixon’s decision to open relations with the People’s Republic of China. Since the Communist victory in China’s civil war in 1949, the USA had refused to recognise the Beijing government, instead treating Taiwan as the legitimate Chinese government. Nixon, a lifelong anti-communist, recognised that China and the Soviet Union had their own territorial disputes and that playing the two powers against each other could benefit American diplomacy — a strategy known as triangular diplomacy.
In February 1972, Nixon visited China — the first sitting US president to do so — meeting Communist leader Mao Zedong. The visit, nicknamed “ping-pong diplomacy” because it had been preceded by a cultural exchange between the two countries’ table tennis teams, opened the door to normalisation of relations, completed under President Carter in 1979.
The Limits of Détente
Détente had its limits. The Helsinki Accords (1975), signed by 35 nations including the USA and USSR, recognised post-war European borders and contained human rights commitments — which Soviet dissidents later used to hold their government to account. However, détente did not stop superpower competition in the developing world. The USA and USSR backed rival factions in conflicts in Angola, Ethiopia and elsewhere throughout the 1970s. American confidence was further damaged by President Carter’s perceived weakness during the 1979 Tehran hostage crisis. The Soviet invasion of Afghanistan in December 1979 was the decisive blow: Carter withdrew the USA from the 1980 Moscow Olympics and the US Senate refused to ratify SALT II, effectively ending the détente era. By the time Ronald Reagan took office in January 1981, the mood in Washington had decisively shifted back towards confrontation with the Soviet Union.
Ronald Reagan entered office in 1981 determined to reverse détente and reassert American strength. In a 1983 speech he described the Soviet Union as an Evil Empire, signalling a return to confrontational rhetoric. Reagan dramatically increased US defence spending and proposed the Strategic Defense Initiative (SDI — nicknamed “Star Wars”), a space-based missile defence system. Historians debate whether SDI was intended to be built or was a negotiating bluff designed to force the Soviets into an unwinnable spending race.
The USA also supported anti-communist forces around the world under the “Reagan Doctrine,” providing arms to groups fighting Soviet-backed governments in Afghanistan, Nicaragua and Angola. The Soviet intervention in Afghanistan (1979–1989) became a costly quagmire for the USSR, often compared to America’s Vietnam experience.
Gorbachev and the End of the Cold War
When Mikhail Gorbachev became Soviet leader in 1985, the USSR faced severe economic stagnation. Gorbachev introduced two transformative reform programmes: perestroika (economic restructuring) and glasnost (openness and greater freedom of expression). He also sought to reduce the Cold War arms burden by negotiating with Reagan. The INF Treaty (1987) eliminated an entire class of nuclear weapons — intermediate-range missiles — for the first time.
Gorbachev’s reforms of the mid-1980s — perestroika (economic restructuring) and glasnost (openness) — were intended to save the Soviet system, but they fatally undermined it by unleashing demands for greater freedoms. By 1989, Soviet satellite states in Eastern Europe were holding free elections; the Berlin Wall fell on 9 November 1989. The USSR itself was dissolved on 25 December 1991.
On the night of 9 November 1989, the East German government announced that citizens could cross freely through the Berlin Wall, which had divided the city since 1961. Crowds gathered and began physically demolishing it. The images broadcast worldwide symbolised the collapse of Communist authority in Eastern Europe. Within months, free elections were held across the former Soviet bloc. Germany was reunified on 3 October 1990. The dissolution of the Soviet Union on 25 December 1991 formally ended the Cold War — a conflict that had structured world affairs for over four decades.