 Although committed to preserving the Soviet state and to its socialist ideals, Gorbachev believed significant reform was necessary, particularly after the 1986 Chernobyl disaster.He withdrew from the Soviet–Afghan War and embarked on summits with United States President Ronald Reagan to limit nuclear weapons and end the Cold War.Domestically, his policy of "glasnost" ("openness") allowed for enhanced freedom of speech and press, while his "perestroika" ("restructuring") sought to decentralize economic decision making to improve efficiency.