Gorbachev - in power from 1985. Glasnost (openess). Perestroika (restructuring). Chernobyl was covered up for a bit though. Not a particularly popular leader, Resigned December 25th 1990. Soviet Union voted out of existence, to be replaced by a Commonwealth of Independent States (CIS).
Mikhail Gorbachev was general secretary of the Soviet Union Communist Party from 1985-1991. He was also the first democratically elected President in 1990.He played a key role in dismantling the Communist grip on power in both the Soviet Union and Eastern Europe. His aspirations for democracy and reform opened up the way for the end of the Cold War and the bringing down of the Berlin Wall.
Mikhail Sergeyevich Gorbachev, He shaped and advocated his policies of perestroika (new thinking) and glasnost (openness) throughout the 1980s, from increasingly powerful platforms. Named in 1985 General Secretary of the Central Committee, at that time the country's most influential post, Gorbachev was elected the first President of the Soviet Union by a reformed parliament in 1989.