Cold War (1985–1991) reduced some strategic arms unilaterally. Fundamental to the dissolution of the Soviet Union, the Gorbachev policy initiatives of Restructuring ("Perestroika") and Openness ("Glasnost") had ripple effects throughout the Soviet world, including eventually making it impossible to reassert central control over Warsaw Pact member states without resorting to military force. On June 12, 1987, Reagan challenged Gorbachev to go further with his reforms and democratization by tearing down the Berlin Wall. In a speech at the Brandenburg Gate next to the wall, Reagan stated: While the aging communist European leaders kept their states in the grip of "normalization", Gorbachev's reformist policies
Anatoly Chernyaev the Soviet Union. He became General Secretary Gorbachev's foreign-policy advisor in 1986 and continued to advise Gorbachev when the latter became President of the Soviet Union. In 2004, Chernyaev donated his diaries from the Gorbachev period to the National Security Archive at George Washington University, which has published portions of them in English translation; according to the editor, "One can confidently say that every bold foreign policy initiative advanced by Gorbachev in the years 1985-1991 bears Chernyaev's mark on it." Since then, the National Security Archive has made available Chernyaev's diaries from 1972 to 1978 with an English translation of