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
Foreign trade of the Soviet Union paying above-market prices for Soviet oil. The membership of Cuba, Mongolia, and Vietnam in Comecon has served Soviet foreign policy interests more than the economic welfare of Comecon members. In general, the more economically developed European members have supported the three less developed members by providing a large market for their exports, often at above-market prices. Most of Cuba's sugar and nickel and all of Mongolia's copper and molybdenum have been imported by the Soviet Union. In addition, the Soviet Union has established naval and air bases in Cuba and Vietnam. Since 1985 Gorbachev has called for an increase in