Communist Party of the Soviet Union along with the institution of free multiparty elections led to a decline in the party's power, and after the dissolution of the Soviet Union, the banning of the party by later last RSFSR President Boris Yeltsin and subsequent first President of an evolving democratic and free market economy of the successor Russian Federation. A number of causes contributed to CPSU's loss of control and the dissolution of the Soviet Union during the early 1990s. Some historians have written that Gorbachev's policy of "glasnost" (political openness) was the root cause, noting that it weakened the party's control over society. Gorbachev maintained
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