Answer: gorbachev

AnswerCrossword Clue
GORBACHEV"Peace is not unity in similarity but unity in diversity." (1990)
GORBACHEVHe instituted glasnost
GORBACHEVWhom Reagan told to "tear down this WALL"
GORBACHEVSoviet president when the Berlin Wall was dismantled
GORBACHEVReagan told him "Tear down this wall!"