No dimension of the Cold War carries a heavier historical weight than the nuclear one. Between 1945 and 1991, the United States and the Soviet Union built arsenals capable of destroying human civilization many times over, and they came closer to using those weapons than most citizens of either country ever realized. The story of how the bomb was conceived, raced, restrained, and finally partly unwound is the central narrative of this overview.
From fission to arsenal: 1938–1949
The physics was European. Otto Hahn and Fritz Strassmann demonstrated nuclear fission in Berlin in December 1938; Lise Meitner and Otto Frisch, working in exile, gave the first theoretical account weeks later. The weapon was American. The Manhattan Project, launched in 1942 under General Leslie Groves and J. Robert Oppenheimer, employed more than 130,000 people at a cost of roughly $2 billion in 1940s dollars. The Trinity test at Alamogordo on July 16, 1945 produced a yield of about 21 kilotons. Hiroshima followed on August 6, Nagasaki on August 9. Japan announced surrender on August 15.
The American monopoly lasted four years. The Soviet Union detonated its first atomic device on August 29, 1949, at Semipalatinsk. The arms race was now structural, not optional.
Megatonnage: 1949–1962
The next phase was driven by hydrogen bombs and missiles. The American “Ivy Mike” test of November 1, 1952 produced a yield of 10.4 megatons, roughly 500 times Hiroshima. The Soviet “Joe-4” followed in August 1953. The American Castle Bravo test of March 1, 1954, the first deliverable thermonuclear device, produced 15 megatons and contaminated the Lucky Dragon fishing vessel 80 miles away, an incident that hardened Japanese anti-nuclear opinion for decades. Intercontinental ballistic missiles (ICBMs) entered operational service with both superpowers in 1959, cutting warning time from hours to minutes. By 1962, each side had crossed the threshold of 25,000 warheads’ worth of deployed and reserve capacity.
The closest call: October 1962
The Cuban Missile Crisis remains the only time the superpowers have stood at the nuclear brink. After U-2 photography confirmed the presence of Soviet SS-4 medium-range missiles in Cuba, President Kennedy imposed a naval “quarantine” on October 22. Khrushchev’s first letter of October 26 offered to trade the missiles for a no-invasion pledge; his second, on October 27 — Black Saturday, the day a U-2 was shot down over Cuba and a Soviet submarine nearly launched a nuclear torpedo in the Sargasso Sea — added a demand that American Jupiter missiles be removed from Turkey. Kennedy accepted the first letter publicly and the second in a private assurance. The crisis ended on October 28.
The crisis produced the Moscow–Washington hot line (1963) and the Limited Test Ban Treaty (1963). It also produced, in the words of Robert McNamara, the recognition that nuclear war could not be won and must never be fought.
Arms control: 1963–1991
The Limited Test Ban Treaty of August 5, 1963 banned tests in the atmosphere, outer space, and underwater. SALT I, signed in Moscow on May 26, 1972, produced two instruments: the Anti-Ballistic Missile (ABM) Treaty, which limited each side to two missile-defense sites (reduced to one by a 1974 protocol), and the Interim Agreement, which froze the number of strategic ballistic missile launchers. SALT II, signed in Vienna on June 18, 1979, set detailed numerical ceilings on delivery vehicles, MIRVed missile counts, and throw-weight, but the U.S. Senate never ratified it after the Soviet invasion of Afghanistan in December 1979.
The Reagan–Gorbachev summits produced the Intermediate-Range Nuclear Forces (INF) Treaty of December 1987, the first agreement to eliminate an entire class of nuclear weapons — the Strategic Arms Reduction Treaty (START I) of July 1991, which cut deployed strategic warheads to roughly 6,000 per side. By the time the Soviet Union dissolved in December 1991, more than 70,000 nuclear warheads had been built worldwide; the inheritance of that arsenal by Russia, Ukraine, Belarus, and Kazakhstan became one of the great, and surprisingly successful, nonproliferation challenges of the 1990s.
Proliferation beyond the superpowers
The nonproliferation regime is built on the Nuclear Non-Proliferation Treaty (NPT), opened for signature July 1, 1968, in force March 5, 1970. The treaty recognizes five nuclear-weapon states (the United States, the Soviet Union/Russia, the United Kingdom, France, and China) and requires all other parties to forgo nuclear weapons. India tested a “peaceful nuclear explosive” in 1974 and a full range of weapons in May 1998. Pakistan followed with tests on May 28, 1998. Israel has maintained a deliberate policy of nuclear ambiguity since the late 1960s, with an estimated arsenal of 100 to 200 warheads. North Korea announced its withdrawal from the NPT in 2003 and has conducted six nuclear tests, the most recent in September 2017. South Africa is the only state to have developed nuclear weapons and then dismantled them voluntarily, between 1989 and 1991.
These cases, disputed Iranian program, define the contemporary proliferation problem and connect the Cold War history of the bomb to twenty-first-century nuclear order.
Key sources
- Richard Rhodes, The Making of the Atomic Bomb (Simon & Schuster, 1986)
- John Lewis Gaddis, The Cold War: A New History (Penguin, 2005)
- Lawrence Freedman, Kennedy’s Wars: Berlin, Cuba, Laos, and Vietnam (Oxford University Press, 2000)
- Vladislav Zubok, A Failed Empire: The Soviet Union in the Cold War from Stalin to Gorbachev (University of North Carolina Press, 2007)
- Odd Arne Westad, The Cold War: A World History (Basic Books, 2017)