Negotiations for START I began in May 1982 , though continued negotiation of the START process was delayed several times because US agreement terms were considered non-negotiable by pre-Gorbachev Soviet rulers . President Reagan 's introduction of the Strategic Defense Initiative ( SDI ) program in 1983 was viewed as a threat by the Soviet Union , and the Soviets withdrew from setting a timetable for further negotiations . In January 1985 , however , U.S. Secretary of State George Shultz and Soviet Foreign Minister Andrey Gromyko discussed a formula for a three part negotiation strategy that included intermediate-range forces , strategic defense , and missile defense . During the Reykjavik summit between Presidents Ronald Reagan and Mikhail Gorbachev in October 1986 , negotiations towards the implementation of the START Program were accelerated . Negotiations turned towards the reduction of strategic weapons when the Intermediate-Range Nuclear Forces Treaty was signed in December 1987 . Despite this , a dramatic nuclear arms race proceeded during the 1980s , and essentially ended in 1991 by nuclear parity preservation at a level of more than ten thousand strategic warheads on both sides
Reykjavik summit
Reykjavík Summit
START I