Gorbachev's plan to have more of a stable Soviet Union failed and so came in Boris Yeltsin who wanted a democratic Russia. Yeltsin and Gorbachev were never on the same page and always clashed for what was best for Russia. ... Yeltsin wanted change and the end of Soviet Union, as Russian Republic President made it possible. After being forced out, basically, Gorbachev resigned and left Yeltsin in command. On December 8, 1991 Yeltsin negotiated with Belarus and the Ukraine to terminate the USSR. ...
THE COLLAPSE OF THE SOVIET UNION The main reason for the decline, and ultimate collapse, of the Soviet Union was the failure of the economic system. The need to improve economic performance led to wide-ranging changes in the economy and politics. The failure of the economic system was due to inherent weaknesses that were escalated by external factors. In particular the Cold War (1945-1989) led to enormous spending on the arms race and the space race. This hastened the demise of the Soviet Union. ...