START was one of the first nuclear disarmament treaties to go into effect during the breakdown of the Soviet Union. Having been drafted in the 1980s, it was signed in June 1991, and involved one of the most complex plans for nuclear disarmament in history. It limited overall warhead counts to 5,000, and ICBMs to 2,500. The fact that it was negotiated through the 1980s and implemented in the 1990s is significant, as it showed it was an influential factor in ending the Cold War.