When USSR leader Mikhail Gorbachev spoke to the United Nations in 1988, his country and the United States were still very much in the midst of the Cold War. Although some impasses had been made during the period of "glasnost" (openness and transparency) that Gorbachev had started in 1986, there was still a lot of tension between the USSR and much of the rest of the world.
Gorbachev began his speech to the United Nations by acknowledging the reason why he chose to come speak to them:
We have come here to show our respect for the United Nations, which increasingly has been manifesting its ability to act as a unique international center in the service of peace and security.
During his speech, Gorbachev announced that the Soviet military presence in Eastern Europe and along the border of China would be significantly decreased. He also announced that, in total, the military would be reduce by half a million soldiers in the next two years.
By announcing these sweeping disarmament reforms on the world stage, Gorbachev was able to show how seriously he and the Soviet Union were about resolving the conflicts of the Cold War. This forum also allowed him to speak about the need for other countries — such as the United States — to reduce its nuclear and conventional weapons.