By the 1970s the height of the Cold War had passed: both countries survived the Cuban Missile Crisis, when the nuclear forces of both were on a hair trigger. Both countries had slowed down production of missiles, but offset it with a troubling development of multiple warhead missiles, enabling a single intercontinental ballistic missile to strike multiple targets (and evade anti-ballistic missile defenses). Then both countries sat down to discuss further development — the SALT agreements — which just after the fall of the USSR led to the START pact.

On this day, July 31, in 1991 the START I agreement was signed by President Ronald Reagan and Russian leader Mikhail Gorbachev in Moscow, Russia.

Under the agreement, which lasted until 2008, each side would deploy no more than 2,500 warheads on any ICBM, and would keep a maximum of 600 of ICBMs. Both sides reduced their armaments accordingly, with Russia transferring nuclear weapons from Kazakhstan and other neighboring republics. Between 2008 and 2011, when a new START treaty was negotiated with Russian President Dmitri Medvedev, the two sides agreed to keep the current weapons count unchanged.