March 1985: Mikhail Gorbachev elected general secretary.October 1985: Gorbachev introduces perestroika, his plan for political and economic restructuring. November 1989: Popular revolutions undo communist regimes in East Germany and later Eastern Europe. Berlin Wall falls. February 1990: Communist Party surrenders its power monopoly. A draft law allows republics to break away from Soviet Union after simple referendum. Huge pro-reform rallies take place. July 1990: Gorbachev tells conservatives at party congress "no one will be permitted to wreck perestroika." December 1990: Conservatives demand action to stop country's disintegration. Foreign Minister Eduard Shevardnadze resigns, citing "looming dictatorship." Gorbachev secures election of Gennady Yanayev as vice president he can trust. January 1991: Soviet military cracks down on Baltic independence movements. February 1991: Gorbachev reaffirms commitment to Communism. April 1991: Gorbachev reaches "nine-plus-one" agreement with republican leaders to sign new union treaty. June 12, 1991: Reformer Boris Yeltsin elected president of Russian republic in popular vote. July 1991: Gorbachev wins promise of more Western aid conditioned on further reform. Aug. 19, 1991: Yanayev takes over as acting president and declares a state of emergency in areas of the Soviet Union.